Method of manufacturing semiconductor device

ABSTRACT

A method includes: forming a thin film on a substrate by performing a cycle a predetermined number of times, the cycle including: (a) supplying a source gas to the substrate in a process chamber; and (b) supplying a reactive gas to the substrate in the process chamber, wherein at least one of (a) and (b) includes: (c) supplying the source gas or the reactive gas at a first flow rate with exhaust of an inside of the process chamber being suspended until an inner pressure of the process chamber reaches a predetermined pressure; and (d) supplying the source gas or the reactive gas at a second flow rate less than the first flow rate with exhaust of the inside of the process chamber being performed while maintaining the inner pressure of the process chamber at the predetermined pressure after the inner pressure of the process chamber reaches the predetermined pressure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority under 35 U.S.C. §119(a)-(d) toApplication No. JP 2012-064465 filed on Mar. 21, 2012, and toApplication No. JP 2013-030452 filed on Feb. 19, 2013, the entirecontents of each of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing asemiconductor device including a process of forming a thin film on asubstrate, a substrate processing apparatus, and a non-transitorycomputer-readable recording medium.

BACKGROUND

In some cases, a process of forming a thin film, such as a silicon oxide(SiO) film or a silicon nitride (SiN) film, on a substrate may beperformed as a process included in a process of manufacturing asemiconductor device. The silicon oxide (SiO) film has high insulatingproperties and low dielectric properties and is thus widely used as aninsulating film or an interlayer film. In addition, the silicon nitride(SiN) film has high insulating properties, high corrosion resistance,low dielectric properties, high film stress controllability, etc., andis thus widely used as an insulating film, a mask film, a chargeaccumulating film, or a stress control film. In addition, a technique offorming a thin film, such as a silicon carbonitride (SiCN) film, asilicon oxycarbonitride (SiOCN) film, a silicon oxycarbide (SiOC) film,or a silicon boron carbonitride (SiBCN) film, by adding carbon (C)and/or boron (B) to the silicon oxide (SiO) film and the silicon nitride(SiN) film has been known. An etching resistance of a thin film may beenhanced by adding carbon (C) thereto.

SUMMARY

A silicon oxycarbide (SiOC) film may be formed by supplying a source gascontaining silicon (Si) (Si-source), a reactive gas containing oxygen(O) (oxygen-containing gas), and a reactive gas containing carbon (C)(carbon-containing gas) to a substrate in a process chamber. A siliconcarbonitride (SiCN) film may be formed by supplying a Si source, areactive gas containing nitrogen (N) (nitrogen-containing gas), and acarbon-containing gas to the substrate in the process chamber.

In order to increase the concentrations of oxygen, nitrogen, carbon,etc. contained in a thin film, such as the SiOC film or the SiCN film,it is effective to increase the flow rates of reactive gases (anoxygen-containing gas, a nitrogen-containing gas, and acarbon-containing gas) to be supplied into the process chamber. However,if the flow rates of the reactive gases increase, a total supply rate(consumption rate or usage rate) of the reactive gas may increase,thereby increasing film-forming costs. In particular, when expensivegases are used as reactive gases, film-forming costs are very high.

It is an object of the present invention to provide a method ofmanufacturing a semiconductor device, which is capable of reducing atotal supply rate of reactive gases without lowering the concentrationsof, for example, oxygen, nitrogen, and carbon contained in a thin film,a substrate processing apparatus, and a non-transitory computer-readablerecording medium.

According to one aspect of the present invention, there is provided amethod of manufacturing a semiconductor device, including: forming athin film on a substrate by performing a cycle a predetermined number oftimes, the cycle including: (a) supplying a source gas to the substratein a process chamber; and (b) supplying a reactive gas to the substratein the process chamber, wherein at least one of the steps (a) and (b)includes: (c) supplying the source gas or the reactive gas at a firstflow rate with an exhaust of an inside of the process chamber beingsuspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

According to another aspect of the present invention, there is provideda substrate processing apparatus including: a process chamber configuredto accommodate a substrate; a source gas supply system configured tosupply a source gas into the process chamber; a reactive gas supplysystem configured to supply a reactive gas into the process chamber; anexhaust system configured to exhaust an inside of the process chamber; apressure regulator configured to regulate pressure in the processchamber; and a control unit configured to control the source gas supplysystem, the reactive gas supply system, the exhaust system, and thepressure regulator to form a thin film on the substrate by performing acycle a predetermined number of times, the cycle including: (a)supplying a source gas to the substrate in a process chamber; and (b)supplying a reactive gas to the substrate in the process chamber,wherein at least one of the steps (a) and (b) includes: (c) supplyingthe source gas or the reactive gas at a first flow rate with an exhaustof an inside of the process chamber being suspended until an innerpressure of the process chamber reaches a predetermined pressure; and(d) supplying the source gas or the reactive gas at a second flow rateless than the first flow rate with the exhaust of the inside of theprocess chamber being performed while maintaining the inner pressure ofthe process chamber at the predetermined pressure after the innerpressure of the process chamber reaches the predetermined pressure.

According to still another aspect of the present invention, there isprovided a non-transitory computer-readable recording medium storing aprogram that causes a computer to perform a sequence of forming a thinfilm on a substrate by performing a cycle a predetermined number oftimes, the cycle including: (a) supplying a source gas to the substratein a process chamber; and (b) supplying a reactive gas to the substratein the process chamber, wherein at least one of the sequences (a) and(b) includes: (c) supplying the source gas or the reactive gas at afirst flow rate with an exhaust of an inside of the process chamberbeing suspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration view of a vertical processingfurnace of a substrate processing apparatus according to an exemplaryembodiment of the present invention, showing a portion of the processingfurnace in a longitudinal cross-sectional view.

FIG. 2 is a schematic configuration view of the vertical processingfurnace of the substrate processing apparatus according to an exemplaryembodiment of the present invention, showing the portion of theprocessing furnace in a cross-sectional view taken along line A-A ofFIG. 1.

FIG. 3 is a schematic configuration view of a controller of thesubstrate processing apparatus according to an exemplarily embodiment ofthe present invention, showing a control system of the controller in ablock diagram.

FIG. 4 is a view showing a film-forming flow according to a firstembodiment of the present invention.

FIG. 5 is a view showing gas supply timing in a film-forming sequenceaccording to the first embodiment of the present invention.

FIG. 6 is a view showing a film-forming flow according to a secondembodiment of the present invention.

FIG. 7 is a view showing gas supply timing in a film-forming sequenceaccording to the second embodiment of the present invention.

FIG. 8 is a diagram illustrating the relationship among a flow rate of areactive gas (TEA), a flow rate of an inert gas (N₂), pressure in aprocess chamber, a degree of opening of an exhaust valve (APC valve)during a reactive gas (TEA) supply process included in a film-formingsequence according to an embodiment of the present invention.

FIG. 9 is a view showing gas supply timing in a film-forming sequenceaccording to another embodiment of the present invention.

DETAILED DESCRIPTION

First Embodiment of the Present Invention

A first embodiment of the present invention will now be described withreference to the appended drawings.

(1) Configuration of Substrate Processing Apparatus

FIG. 1 is a schematic configuration view of a vertical processingfurnace 202 of a substrate processing apparatus according to anexemplary embodiment of the present invention, showing a portion of theprocessing furnace 202 in a longitudinal cross-sectional view. FIG. 2 isa schematic configuration view of the vertical processing furnace 202according to an exemplary embodiment of the present invention, showingthe portion of the processing furnace 202 in a cross-sectional viewtaken along line A-A of FIG. 1.

As illustrated in FIG. 1, the processing furnace 202 includes a heater207 serving as a heating unit (heating mechanism). The heater 207 has acylindrical shape and is supported by a heater base (not shown) servingas a holding plate to be vertically installed. In addition, the heater207 functions as an activation mechanism (excitation unit) configured tothermally activate (excite) a gas as will be described below.

A reaction tube 203 constituting a reaction container (processingcontainer) to be concentric with the heater 207 is installed inside theheater 207. The reaction tube 203 is formed of a heat-resistantmaterial, such as quartz (SiO₂), silicon carbide (SiC), or the like, andhas a cylindrical shape with an upper end closed and a lower end open. Aprocess chamber 201 is formed in a hollow tubular portion of thereaction tube 203, and is configured such that wafers 200 serving assubstrates may be accommodated by a boat 217 (to be described below)aligned in a horizontal posture in a multi-stage in a verticaldirection.

A first nozzle 249 a, a second nozzle 249 b, and a third nozzle 249 care installed in the process chamber 201 to pass through a lower portionof the reaction tube 203. A first gas supply pipe 232 a, a second gassupply pipe 232 b and a third gas supply pipe 232 c are connected to thefirst nozzle 249 a, the second nozzle 249 b and the third nozzle 249 c,respectively. A fourth gas supply pipe 232 d is connected to the thirdgas supply pipe 232 c. As described above, the three nozzles 249 a, 249b, and 249 c and the four gas supply pipes 232 a, 232 b, 232 c, and 232d are installed at the reaction tube 203 to supply a plurality of types(here, four types) of gases into the process chamber 201.

A manifold formed of metal and configured to support the reaction tube203 may be installed under the reaction tube 203, and the nozzles 249 a,249 b, and 249 c may be installed to pass through a sidewall of themetal manifold. In this case, an exhaust pipe 231 (to be describedlater) may further be installed at the metal manifold. Alternatively,the exhaust pipe 231 may be installed at a lower portion of the reactiontube 203 instead of the metal manifold. As described above, a furnaceport of the processing furnace 202 may be formed of a metal, and thenozzles 249 a, 249 b, and 249 c or the like may be installed at themetal furnace port.

A mass flow controller (MFC) 241 a serving as a flow rate controller(flow rate control unit) and a valve 243 a serving as an opening/closingvalve are installed at the first gas supply pipe 232 a in sequence froman upstream side. In addition, a first inert gas supply pipe 232 e isconnected to the first gas supply pipe 232 a downstream from the valve243 a. A mass flow controller 241 e serving as a flow rate controller(flow rate control unit) and a valve 243 e serving as an opening/closingvalve are installed at the first inert gas supply pipe 232 e in sequencefrom the upstream side. Further, the above-mentioned first nozzle 249 ais connected to a tip section of the first gas supply pipe 232 a. Thefirst nozzle 249 a is installed in an arc-shaped space between an innerwall of the reaction tube 203 and the wafer 200 from a lower portion toan upper portion of the inner wall of the reaction tube 203 to stand upin a stacking direction of the wafers 200. That is, the first nozzle 249a is installed in a region horizontally surrounding a wafer arrangementregion, in which the wafers 200 are arranged, which is a side of thewafer arrangement region, along the wafer arrangement region. The firstnozzle 249 a is constituted by an L-shaped long nozzle, and has ahorizontal section installed to pass through a lower sidewall of thereaction tube 203 and a vertical section installed to stand up at leastfrom one end side to the other end side of the wafer arrangement region.A gas supply hole 250 a configured to supply a gas is formed in a sidesurface of the first nozzle 249 a. The gas supply hole 250 a is openedtoward a center of the reaction tube 203 so that a gas may be suppliedtoward the wafer 200. The plurality of gas supply holes 250 a are formedfrom the lower portion to the upper portion of the reaction tube 203,have the same opening area, and are formed at the same opening pitch.

A first gas supply system mainly includes the first gas supply pipe 232a, the mass flow controller 241 a, and the valve 243 a. The first nozzle249 a may further be included in the first gas supply system. Further, afirst inert gas supply system mainly includes the first inert gas supplypipe 232 e, the mass flow controller 241 e, and the valve 243 e. Thefirst inert gas supply system also functions as a purge gas supplysystem.

A mass flow controller (MFC) 241 b serving as a flow rate controller(flow rate control unit) and a valve 243 b serving as an opening/closingvalve are installed at the second gas supply pipe 232 b in sequence fromthe upstream side. In addition, a second inert gas supply pipe 232 f isconnected to the second gas supply pipe 232 b downstream from the valve243 b. A mass flow controller 241 f serving as a flow rate controller(flow rate control unit) and a valve 243 f serving as an opening/closingvalve are installed at the second inert gas supply pipe 232 f insequence from the upstream side. Further, the above-mentioned secondnozzle 249 b is connected to a tip section of the second gas supply pipe232 b. The second nozzle 249 b is installed in an arc-shaped spacebetween the inner wall of the reaction tube 203 and the wafer 200 fromthe lower portion to the upper portion of the inner wall of the reactiontube 203 to stand up in the stacking direction of the wafers 200. Thatis, the second nozzle 249 b is installed at a region surrounding thewafer arrangement region in which the wafers 200 are arranged, which isa side of the wafer arrangement region, along the wafer arrangementregion. The second nozzle 249 b is constituted by an L-shaped longnozzle, and has a horizontal section installed to pass through the lowersidewall of the reaction tube 203 and a vertical section installed tostand up at least from the one end side to the other end side of thewafer arrangement region. A gas supply hole 250 b configured to supply agas is formed in a side surface of the second nozzle 249 b. The gassupply hole 250 b is opened toward the center of the reaction tube 203so that a gas may be supplied toward the wafer 200. The plurality of gassupply holes 250 b are installed from the lower portion to the upperportion of the reaction tube 203, have the same opening area, and areinstalled at the same opening pitch.

A second gas supply system mainly includes the second gas supply pipe232 b, the mass flow controller 241 b and the valve 243 b. The secondnozzle 249 b may be further included in the second gas supply system.Further, a second inert gas supply system mainly includes the secondinert gas supply pipe 232 f, the mass flow controller 241 f, and thevalve 243 f. The second inert gas supply system may function as a purgegas supply system.

A mass flow controller (MFC) 241 c serving as a flow rate controller(flow rate control unit) and a valve 243 c serving as an opening/closingvalve are installed at the third gas supply pipe 232 c in sequence fromthe upstream side. In addition, the fourth gas supply pipe 232 d isconnected to the third gas supply pipe 232 c downstream from the valve243 c. A mass flow controller 241 d serving as a flow rate controller(flow rate control unit) and a valve 243 d serving as an opening/closingvalve are installed at the fourth gas supply pipe 232 d in sequence fromthe upstream side. Further, a third inert gas supply pipe 232 g isconnected to the third gas supply pipe 232 c downstream from aconnecting place to the fourth gas supply pipe 232 d. A mass flowcontroller 241 g serving as a flow rate controller (flow rate controlunit) and a valve 243 g serving as an opening/closing valve areinstalled at the third inert gas supply pipe 232 g in sequence from theupstream side. In addition, the above-mentioned third nozzle 249 c isconnected to a tip section of the third gas supply pipe 232 c. The thirdnozzle 249 c is installed in an arc-shaped space between the inner wallof the reaction tube 203 and the wafer 200 from the lower portion to theupper portion of the inner wall of the reaction tube 203 to stand up inthe stacking direction of the wafers 200. That is, the third nozzle 249c is installed at the region horizontally surrounding the waferarrangement region in which the wafers 200 are arranged, which is a sideof the wafer arrangement region, along the wafer arrangement region. Thethird nozzle 249 c is constituted by an L-shaped long nozzle, and has ahorizontal section installed to pass through the lower sidewall of thereaction tube 203 and a vertical section installed to stand up at leastfrom the one end side to the other end side of the wafer arrangementregion. A gas supply hole 250 c configured to supply a gas is formed ina side surface of the third nozzle 249 c. The gas supply hole 250 c isopened toward the center of the reaction tube 203 so that a gas may besupplied toward the wafer 200. The plurality of gas supply holes 250 care formed from the lower portion to the upper portion of the reactiontube 203, have the same opening area, and are installed at the sameopening pitch.

A third gas supply system mainly includes the third gas supply pipe 232c, the mass flow controller 241 c, and the valve 243 c. The third nozzle249 c may be further included in the third gas supply system. Further, afourth gas supply system mainly includes the fourth gas supply pipe 232d, the mass flow controller 241 d, and the valve 243 d. In addition, thethird nozzle 249 c disposed at a downstream side of a connecting sectionof the third gas supply pipe 232 c with the fourth gas supply pipe 232 dmay be included in the fourth gas supply system. In addition, a thirdinert gas supply system mainly includes the third inert gas supply pipe232 g, the mass flow controller 241 g, and the valve 243 g. The thirdinert gas supply system also functions as a purge gas supply system.

As described above, in the method of supplying a gas according to thefirst embodiment, the gas is conveyed via the nozzles 249 a, 249 b, and249 c disposed in an arc-shaped longitudinal long space defined by theinner wall of the reaction tube 203 and the end section of the pluralityof stacked wafers 200, the gas is firstly ejected into the reaction tube203 near the wafer 200 through the gas supply holes 250 a, 250 b, and250 c opened at the nozzles 249 a, 249 b and 249 c, respectively, andthus a main stream of the gas in the reaction tube 203 is in a directionparallel to the surface of the wafer 200, i.e., in a horizontaldirection. According to the above-mentioned configuration, the gas maybe evenly supplied to the wafer 200, and a film thickness of a thin filmformed on the wafer 200 may be uniformized. In addition, while the gasflowing on the surface of the wafer 200, i.e., the gas remaining afterreaction, flows in a direction of an exhaust port, i.e., the exhaustpipe 231 (to be described later), the direction in which the remaininggas flows is appropriately specified at a position of the exhaust portand not limited to the vertical direction.

A chlorosilane-based source gas that is a source gas containing aspecific element and a halogen element, for example, a source gascontaining at least silicon (Si) and chlorine (Cl), is supplied into theprocess chamber 201 via the mass flow controller 241 a, the valve 243 a,and the first nozzle 249 a through the first gas supply pipe 232 a.Here, the chlorosilane-based source gas means a chlorosilane-basedsource material in a gaseous state, for example, a gas obtained byevaporating a chlorosilane-based source material in a liquid state undera normal temperature and a normal pressure, or a chlorosilane-basedsource material in a gaseous state under a normal temperature and anormal pressure. In addition, the chlorosilane-based source materialmeans a silane-based source material including a chloro group which is ahalogen group, and a source material including at least silicon (Si) andchlorine (Cl). That is, here, the chlorosilane-based source material mayrefer to a type of halide. In addition, the term “source material” usedin the present disclosure may refer to “a liquid source material in aliquid state,” “a source gas in a gaseous state,” or both of these.Accordingly, the term “chlorosilane-based source material” used in thepresent disclosure may refer to “a chlorosilane-based source material ina liquid state,” “a chlorosilane-based source gas in a gaseous state,”or both of these. For example, hexachlorodisilane (Si₂Cl₆, abbreviatedto ‘HCDS’) gas may be used as the chlorosilane-based source gas. Inaddition, when the liquid source material in the liquid state is usedunder the normal temperature and normal pressure as the HCDS gas, theliquid source material is evaporated by an evaporation system, such asan evaporator, a bubbler, or the like, to be supplied as a source gas(HCDS gas).

For example, a gas containing an amine, i.e., an amine-based gas, whichis a reactive gas (first reactive gas) containing carbon (C) andnitrogen (N), is supplied into the process chamber 201 via the mass flowcontroller 241 b, the valve 243 b, and the second nozzle 249 b throughthe second gas supply pipe 232 b. Here, the amine-based gas is an aminein a gaseous state, for example, a gas obtained by evaporating an aminein a liquid state under the normal temperature and normal pressure, or agas containing an amine group such as amine in a gaseous state under thenormal temperature and normal pressure. The amine-based gas includes anamine, such as ethylamine, methylamine, propylamine, isopropylamine,butylamine, isobutylamine, or the like. Here, “amine” is a general nameof a compound in which a hydrogen atom of ammonia (NH₃) is substitutedwith a hydrocarbon group such as an alkyl group or the like. That is,the amine includes a hydrocarbon group such as an alkyl group or thelike, which is a ligand including a carbon atom. The amine-based gas mayrefer to a gas containing no silicon because the gas includes threeelements of carbon (C), nitrogen (N), and hydrogen (H) but does notinclude silicon (Si), and may refer to a gas containing no silicon andno metal because the gas does not include silicon or a metal. Inaddition, the amine-based gas may be a nitrogen-containing gas, acarbon-containing gas, or a hydrogen-containing gas. The amine-based gasmay be a gas containing only three elements of carbon (C), nitrogen (N),and hydrogen (H) constituting the amine group. In addition, the term“amine” used in the present disclosure may mean “an amine in a liquidstate,” “an amine-based gas in a gaseous state,” or both of these. Forexample, triethylamine [(C₂H₅)₃N, abbreviated to TEA] gas may be used asthe amine-based gas. In addition, when an amine such as TEA that is in aliquid state under a normal temperature and normal pressure is used, theamine in the liquid state is evaporated by an evaporation system, suchas an evaporator, a bubbler, or the like, to be supplied as a firstreactive gas (TEA gas).

For example, a gas including oxygen (O) (oxygen-containing gas), i.e.,an oxidizing gas (oxidant gas), which is a reactive gas that isdifferent from the first reactive gas (second reactive gas), is suppliedinto the process chamber 201 via the mass flow controller 241 c, thevalve 243 c, and the third nozzle 249 c through the third gas supplypipe 232 c. For example, oxygen (O₂) gas may be used as theoxygen-containing gas.

For example, a gas including nitrogen (N) (nitrogen-containing gas),i.e., a nitriding gas (nitridant gas), which is a reactive gas that isdifferent from the first reactive gas (second reactive gas), is suppliedinto the process chamber 201 via the mass flow controller 241 d, thevalve 243 d, the third gas supply pipe 232 c, and the third nozzle 249 cthrough the fourth gas supply pipe 232 d. For example, ammonia (NH₃) gasmay be used as the nitrogen-containing gas.

For example, nitrogen (N₂) gas, which is an inert gas, is supplied intothe process chamber 201 via the mass flow controllers 241 e, 241 f, and241 g, the valves 243 e, 243 f, and 243 g, the gas supply pipes 232 a,232 b, and 232 c, and the nozzles 249 a, 249 b, and 249 c through theinert gas supply pipes 232 e, 232 f, and 232 g.

In addition, for example, when the above-mentioned gases flow throughthe respective gas supply pipes, a source gas supply system configuredto supply a source gas including a specific element and a halogen group,i.e., a chlorosilane-based source gas supply system, is constituted bythe first gas supply system. Further, the chlorosilane-based source gassupply system is also referred to simply as a chlorosilane-based sourcematerial supply system. Furthermore, a reactive gas supply system (firstreactive gas supply system), i.e., an amine-based gas supply system, isconstituted by the second gas supply system. In addition, theamine-based gas supply system is also referred to simply as an aminesupply system. Further, a reactive gas supply system (second reactivegas supply system), i.e., an oxygen-containing gas supply system servingas an oxidizing gas supply system, is constituted by the third gassupply system. Furthermore, a reactive gas supply system (secondreactive gas supply system), i.e., a nitrogen-containing gas supplysystem serving as a nitriding gas supply system, is constituted by thefourth gas supply system.

The exhaust pipe 231 configured to exhaust an atmosphere in the processchamber 201 is installed in the reaction tube 203. When seen in atransverse cross-sectional view as shown in FIG. 2, the exhaust pipe 231is installed at a side of the reaction tube 203 opposite to a side inwhich the gas supply hole 250 a of the first nozzle 249 a, the gassupply hole 250 b of the second nozzle 249 b, and the gas supply hole250 c of the third nozzle 249 c are formed, i.e., an opposite side ofthe gas supply holes 250 a, 250 b, and 250 c via the wafer 200. Inaddition, when seen in a longitudinal cross-sectional view as shown inFIG. 1, the exhaust pipe 231 is installed under a place in which the gassupply holes 250 a, 250 b, and 250 c are formed. According to theconfiguration, the gas supplied in the vicinity of the wafer 200 in theprocess chamber 201 through the gas supply holes 250 a, 250 b, and 250 cflows in a horizontal direction, i.e., in a direction parallel to thesurface of the wafer 200, then flows downward, and then is exhaustedthrough the exhaust pipe 231. A main flow of the gas in the processchamber 201 becomes a flow in the horizontal direction as describedabove.

A vacuum pump 246 serving as a vacuum exhaust apparatus is connected tothe exhaust pipe 231 via a pressure sensor 245 serving as a pressuredetector (pressure detection unit) configured to detect the pressure inthe process chamber 201 and an APC (Auto Pressure Controller) valve 244serving as a pressure regulator (pressure regulation unit) which is anexhaust valve. In addition, the APC valve 244 is a valve configured toperform the vacuum exhaust of the inside of the process chamber 201 andstop the vacuum exhaust by opening/closing the valve in a state in whichthe vacuum pump 246 is operated, and configured to regulate the pressurein the process chamber 201 by adjusting a valve opening angle in a statein which the vacuum pump 246 is operated. An exhaust system, i.e., anexhaust line, mainly includes the exhaust pipe 231, the APC valve 244,and the pressure sensor 245. The vacuum pump 246 may further be includedin the exhaust system (exhaust line). The exhaust system (exhaust line)is configured to perform the vacuum exhaust such that the pressure inthe process chamber 201 arrives at a predetermined pressure (vacuumlevel) by adjusting the valve opening angle of the APC valve 244 basedon the pressure information detected by the pressure sensor 245 whileoperating the vacuum pump 246.

A seal cap 219 serving as a furnace port cover configured tohermetically seal the lower end opening of the reaction tube 203 isinstalled under the reaction tube 203. The seal cap 219 is configured toabut the lower end of the reaction tube 203 from a lower side in thevertical direction. The seal cap 219 is formed of a metal such asstainless steel or the like, and has a disc shape. An O-ring 220 servingas a seal member configured to abut the lower end of the reaction tube203 is installed at an upper surface of the seal cap 219. A rotarymechanism 267 configured to rotate the boat 217 serving as a substrateholder (to be described later) is installed at a side of the seal cap219 opposite to the process chamber 201. A rotary shaft 255 of therotary mechanism 267 is connected to the boat 217 through the seal cap219. The rotary mechanism 267 is configured to rotate the boat 217 torotate the wafer 200. The seal cap 219 is constituted to be raised andlowered in the vertical direction by a boat elevator 115 serving as araising/lowering mechanism vertically installed at the outside of thereaction tube 203. The boat elevator 115 is configured to load andunload the boat 217 into and from the process chamber 201 by raising andlowering the seal cap 219. That is, the boat elevator 115 is constitutedby a conveyance apparatus (conveyance mechanism) configured to conveythe boat 217, i.e., the wafer 200, to/from the process chamber 201.

The boat 217 serving as a substrate support member is formed of a heatresistant material, such as quartz, silicon carbide, or the like, andconfigured to concentrically align the plurality of wafers 200 in ahorizontal posture and support the wafers 200 in a multi-stage. Inaddition, an insulating member 218 formed of a heat resistant material,such as quartz, silicon carbide, or the like, is installed under theboat 217 so that heat from the heater 207 cannot be easily transferredtoward the seal cap 219. Further, the insulating member 218 may beconstituted by a plurality of insulating plates formed of a heatresistant material, such as quartz, silicon carbide, or the like, and aninsulating plate holder configured to support the insulating plate in ahorizontal posture in a multi-stage.

A temperature sensor 263 serving as a temperature detector is installedin the reaction tube 203, and an electrical connection state to theheater 207 is adjusted based on the temperature information detected bythe temperature sensor 263 so that the temperature in the processchamber 201 may have a desired temperature distribution. The temperaturesensor 263 has an L shape similar to the nozzles 249 a, 249 b, and 249c, and is installed along the inner wall of the reaction tube 203.

As shown in FIG. 3, a controller 121 serving as a control unit (controlunit) is constituted by a computer including a central processing unit(CPU) 121 a, a random access memory (RAM) 121 b, a memory device 121 c,and an input/output (I/O) port 121 d. The RAM 121 b, the memory device121 c and the I/O port 121 d are configured to exchange data with theCPU 121 a via an internal bus 121 e. An input/output (I/O) device 122constituted by, for example, a touch panel or the like, is connected tothe controller 121.

The memory device 121 c is constituted by, for example, a flash memory,a hard disk drive (HDD), or the like. A control program configured tocontrol an operation of a substrate processing apparatus or a processrecipe in which a sequence or conditions of substrate processing (to bedescribed later) is readably stored in the memory device 121 c. Inaddition, the process recipe is provided by assembling sequences in asubstrate processing process (to be described below) to be performed inthe controller 121 to obtain a predetermined result, and functions as aprogram. Hereinafter, the process recipe or the control program isgenerally and simply referred to as a program. In addition, the term“program” used in the present disclosure may include only the processrecipe, only the control program, or both of these. Further, the RAM 121b is constituted by a memory region (work area) in which a program ordata read by the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the above-mentioned mass flowcontrollers 241 a, 241 b, 241 c, 241 d, 241 e, 241 f, and 241 g, thevalves 243 a, 243 b, 243 c, 243 d, 243 e, 243 f, and 243 g, the pressuresensor 245, the APC valve 244, the vacuum pump 246, the heater 207, thetemperature sensor 263, the rotary mechanism 267, the boat elevator 115,etc.

The CPU 121 a is configured to read and execute the control program fromthe memory device 121 c, and to read the process recipe from the memorydevice 121 c, according to an operation command input via theinput/output device 122. In addition, the CPU 121 a is configured tocontrol a flow rate control operation of various gases by the mass flowcontrollers 241 a, 241 b, 241 c, 241 d, 241 e, 241 f, and 241 g, anopening/closing operation of the valves 243 a, 243 b, 243 c, 243 d, 243e, 243 f, and 243 g, an opening/closing operation of the APC valve 244,a pressure regulation operation by the APC valve 244 based on thepressure sensor 245, a temperature control operation of the heater 207based on the temperature sensor 263, start and stoppage of the vacuumpump 246, a rotation and rotational speed control operation of the boat217 by the rotary mechanism 267, a raising/lowering operation of theboat 217 by the boat elevator 115, etc., according to contents of theread process recipe.

In addition, the controller 121 is not limited to being constituted byan exclusive computer, and may be constituted by a general computer. Forexample, the controller 121 according to the first embodiment may beconstituted by preparing an external memory device 123 in which theabove-mentioned program is stored (for example, a magnetic tape, amagnetic disk such as a flexible disk, a hard disk, or the like, anoptical disc such as a CD, a DVD, or the like, an optical magnetic discsuch as MO, or a semiconductor memory such as a USB memory, a memorycard, or the like), and installing the program in the general computerusing the above-mentioned external memory device 123. Further, a unitconfigured to supply a program to the computer is not limited to thecase in which the program is supplied via the external memory device123. For example, the program may be supplied using a communicationunit, such as the Internet or an exclusive line, without the externalmemory device 123. In addition, the memory device 121 c or the externalmemory device 123 is constituted by a non-transitory computer-readablerecording medium. Hereinafter, these are generally and simply referredto as non-transitory computer-readable recording media. Further, theterm “non-transitory computer-readable recording medium” used in thepresent disclosure may include only the memory device 121 c, only theexternal memory device 123, or both of these.

(2) Substrate Processing Process

Next, a method of forming a thin film on the wafer 200 using theprocessing furnace 202 of the substrate processing apparatus asdescribed above will be described. In the following description,operations of the respective parts constituting the substrate processingapparatus are controlled by the controller 121.

According to the first embodiment, a thin film is formed on the wafer200 in the process chamber 201 by performing a cycle a predeterminednumber of times (once or more), the cycle including a process ofsupplying a source gas to the wafer 200 and a process of supplying areactive gas to the wafer 200.

During at least one process among the process of supplying the sourcegas and the process of supplying the reactive gas, a first supplyprocess of supplying the source gas or the reactive gas used in the atleast one process at a first flow rate is performed while exhausting ofan atmosphere in the process chamber 201 is suspended until pressure inthe process chamber 201 reaches a predetermined pressure; and a secondsupply process of supplying the source gas or the reactive gas used inthe at least one process at a second flow rate, which is less than thefirst flow rate, is performed in a state in which the atmosphere in theprocess chamber 201 is exhausted while maintaining the predeterminedpressure in the process chamber 201, after the pressure in the processchamber 201 reaches the predetermined pressure.

Further, in the first embodiment, conditions of supplying a plurality oftypes of gases including a plurality of elements forming the thin filmare controlled such that a composition ratio of the thin film has astoichiometric composition or a predetermined composition ratiodifferent from the stoichiometric composition. For example, the supplyconditions are controlled such that at least one element among theplurality of elements forming the thin film is more excessive than theother elements, with respect to the stoichiometric composition.Hereinafter, an example in which the film-forming is performed whilecontrolling a ratio of the plurality of elements forming the thin film,i.e., a composition ratio of the thin film, will be described.

A film-forming sequence according to the first embodiment will now bedescribed with reference to FIGS. 4 and 5 in detail. FIG. 4 is a viewshowing a film-forming flow according to the first embodiment. FIG. 5 isa view showing gas supply timing in the film-forming sequence accordingto the first embodiment.

In addition, here, an example of a process of forming a siliconoxycarbonitride (SiOCN) film or a silicon oxycarbide (SiOC) film, whichis a silicon-based insulating film having a predetermined compositionand a predetermined thickness on the wafer 200 by performing a cycle apredetermined number of times (n times), the cycle including: a processof forming a silicon-containing layer containing chlorine on the wafer200 in the process chamber 201 by supplying HCDS gas (which is achlorosilane-based source gas) as a source gas to the wafer 200 in theprocess chamber 201, a process of forming a first layer containingsilicon, nitrogen, and carbon on the wafer 200 by modifying thesilicon-containing layer containing chlorine by supplying TEA gas (whichis an amine-based gas) as a first reactive gas, and a process of forminga SiOCN film or a SiOC film as a second layer by modifying the firstlayer by supplying O₂ gas (oxygen-containing gas) as a second reactivegas (which is different from the source gas and the first reactive gas)on the wafer 200 in the process chamber 201, will be described.

In addition, here, in a process of supplying the TEA gas among threeprocesses, i.e., the process of supplying the HCDS gas, the process ofsupplying TEA gas, and a process of supplying O₂ gas, a first supplyprocess of supplying the TEA gas at a first flow rate in a state inwhich exhausting an atmosphere in the process chamber 201 is suspendeduntil the pressure in the process chamber 201 reaches a predeterminedpressure (hereinafter referred to as ‘first TEA gas supply process’);and a second supply process of supplying the TEA gas at a second flowrate which is less than the first flow rate in a state in which theatmosphere in the process chamber 201 is exhausted while maintaining thepredetermined pressure in the process chamber 201, after the pressure inthe process chamber 201 reaches the predetermined pressure (hereinafterreferred to as ‘second TEA gas supply process’) will be described.

The term “wafer” used in the present disclosure may mean only “the waferitself,” or “a stacked structure (assembly) of the wafer and a layer orfilm formed on a surface thereof, i.e., the wafer including the layer orfilm formed on the surface thereof.” In addition, the term “a surface ofa wafer” used in the present disclosure may mean “an (exposed) surfaceof the wafer itself,” or “a surface of the layer or film formed on thewafer, i.e., an outermost surface of the wafer, which is a stackedstructure.

Accordingly, an expression “predetermined gas is supplied to a wafer” inthe present disclosure may mean “predetermined gas is directly suppliedto an (exposed) surface of the wafer itself,” or “predetermined gas issupplied to a layer or film formed on the wafer, i.e., the outermostsurface of the wafer, which is a stacked structure.” In addition, anexpression “predetermined layer (or film) is formed on a wafer” in thepresent disclosure may mean “predetermined layer (or film) is directlyformed on an (exposed) surface of the wafer itself,” or “predeterminedlayer (or film) is formed on a layer or film formed on the wafer, i.e.,the outermost surface of the wafer, which is a stacked structure.”

In addition, the term “substrate” used in the present disclosure issimilar to the term “wafer,” and thus “wafer” and “substrate” may beused synonymously in the present disclosure.

Wafer Charging and Boat Loading

When a plurality of wafers 200 are loaded in the boat 217 (wafercharging), the boat 217 supporting the plurality of wafers 200 is raisedby the boat elevator 115 to be loaded into the process chamber 201 (boatloading), as illustrated in FIG. 1. In this state, the seal cap 219seals the lower end of the reaction tube 203 via the O-ring 220.

Pressure Regulation and Temperature Control

The inside of the process chamber 201 is vacuum-exhausted to apredetermined pressure (vacuum level) by the vacuum pump 246. In thiscase, the pressure in the process chamber 201 is measured by thepressure sensor 245, and the APC valve 244 is feedback-controlled basedon the measured pressure information (pressure regulation). In addition,the vacuum pump 246 maintains an always-operating state at least untilthe processing of the wafer 200 is terminated. Further, the inside ofthe process chamber 201 is heated to a desired temperature by the heater207. In this case, an electrical connection state to the heater 207 isfeedback-controlled based on the temperature information detected by thetemperature sensor 263 such that the inside of the process chamber 201has a desired temperature distribution (temperature control). Inaddition, the heating of the inside of the process chamber 201 by theheater 207 is continuously performed at least until the processing ofthe wafer 200 is terminated. Next, rotation of the boat 217 and thewafer 200 is started by the rotary mechanism 267. The rotation of theboat 217 and the wafer 200 by the rotary mechanism 267 is continuouslyperformed at least until the processing of the wafer 200 is terminated.

Process of Forming Silicon Oxycarbonitride Film or Silicon OxycarbideFilm

Next, the following three steps, i.e., steps 1 to 3, are sequentiallyperformed.

Step 1

HCDS Gas Supply

The valve 243 a of the first gas supply pipe 232 a is opened to causeHCDS gas to flow through the first gas supply pipe 232 a. The flow rateof the HCDS gas flowing through the first gas supply pipe 232 a iscontrolled by the mass flow controller 241 a. The flow-rate-controlledHCDS gas is supplied into the process chamber 201 through the gas supplyhole 250 a of the first nozzle 249 a to be exhausted through the exhaustpipe 231. Here, the HCDS gas is supplied to the wafer 200. Here,simultaneously, the valve 243 e is opened to cause N₂ gas, which is aninert gas, to flow through the first inert gas supply pipe 232 e. Theflow rate of the N₂ gas flowing through the first inert gas supply pipe232 e is controlled by the mass flow controller 241 e. Theflow-rate-controlled N₂ gas is supplied into the process chamber 201 tobe exhausted through the exhaust pipe 231 with the HCDS gas.

In addition, here, in order to prevent invasion of HCDS gas into thesecond nozzle 249 b and the third nozzle 249 c, the valves 243 f, and243 g are opened to cause the N₂ gas to flow through the second inertgas supply pipe 232 f and the third inert gas supply pipe 232 g. The N₂gas is supplied into the process chamber 201 to be exhausted through theexhaust pipe 231 via the second gas supply pipe 232 b, the third gassupply pipe 232 c, the second nozzle 249 b, and the third nozzle 249 c.

Here, the APC valve 244 is appropriately adjusted such that the pressurein the process chamber 201 is within a range of, for example, 1 to13,300 Pa, and preferably 20 to 1,330 Pa. A supply flow rate of the HCDSgas controlled by the mass flow controller 241 a is a flow rate within arange of, for example, 1 to 1,000 sccm. Each supply flow rate of the N₂gas controlled by the mass flow controllers 241 e, 241 f, and 241 g is aflow rate within a range of, for example, 100 to 10,000 sccm. A time inwhich the HCDS gas is supplied to the wafer 200, i.e., a gas supply time(exposure time), is a time within a range of, for example, 1 to 120seconds, and preferably 1 to 60 seconds. Here, a temperature of theheater 207 is set such that the temperature of the wafer 200 is atemperature within a range of, for example, 250 to 700° C., preferably300 to 650° C., and more preferably 350 to 600° C. In addition, when thetemperature of the wafer 200 is less than 250° C., a practicalfilm-forming speed may not be accomplished because the HCDS cannot beeasily chemisorbed onto the wafer 200. This problem may be solved byincreasing the temperature of the wafer to 200 to 250° C. or more.Further, when the temperature of the wafer 200 is set to 300° C. ormore, or 350° C. or more, the HCDS may be more sufficiently absorbedonto the wafer 200, and a more sufficient film-forming speed can beaccomplished. In addition, when the temperature of the wafer 200 exceeds700° C., the CVD reaction is strengthened (a gas phase reaction becomesdominant), and thus film thickness uniformity is likely to be degraded,making it difficult to control the film thickness uniformity. When thetemperature of the wafer 200 is set to 700° C. or less, degradation ofthe film thickness uniformity can be suppressed to enable the controlthereof. In particular, when the temperature of the wafer 200 is 650° C.or less, or 600° C. or less, the surface reaction becomes dominant, andthe film thickness uniformity can be easily accomplished to enable easycontrol thereof. Accordingly, the temperature of the wafer 200 may be atemperature within a range of 250 to 700° C., preferably 300 to 650° C.,and more preferably 350 to 600° C.

A silicon-containing layer including chlorine (Cl) and having athickness of, for example, less than one atomic layer to several atomiclayers is formed on the wafer 200 (a base film on a surface of the wafer200) as a seed layer including a specific element (silicon) and ahalogen element (chlorine) by supplying the HCDS gas to the wafer 200under the above-mentioned conditions. A silicon-containing layerincluding Cl may include an adsorption layer of the HCDS gas, a silicon(Si) layer including Cl, or both of these.

Here, the silicon layer including Cl is a general name including acontinuous layer composed of silicon (Si) and including Cl, adiscontinuous layer, and a silicon thin film formed by overlapping themand including Cl. In addition, the continuous layer composed of Si andincluding Cl may refer to a silicon thin film including Cl. Further, Siforming the silicon layer including Cl may include Cl bonds that arecompletely broken, in addition to Cl bonds that are not completelybroken.

The adsorption layer of the HCDS gas also includes a discontinuouschemical adsorption layer in addition to the continuous chemicaladsorption layer of gas molecules of HCDS gas. That is, the adsorptionlayer of the HCDS gas includes a chemical adsorption layer composed ofHCDS molecules and having a thickness of one molecular layer or lessthan one molecular layer. In addition, HCDS (Si₂Cl₆) molecules formingthe adsorption layer of the HCDS gas may also include the Si and Clbonds that are partially broken, i.e., Si_(x)Cl_(y) molecules. That is,the adsorption layer of the HCDS gas includes a continuous chemicaladsorption layer or a discontinuous chemical adsorption layer of Si₂Cl₆molecules and/or Si_(x)Cl_(y) molecules.

In addition, the layer having a thickness of less than one atomic layeris an atomic layer that is discontinuously formed, and the layer havinga thickness of one atomic layer is an atomic layer that is continuouslyformed. Further, the layer having a thickness of less than one molecularlayer is a molecular layer that is discontinuously formed, and the layerhaving a thickness of one molecular layer is a molecular layer that iscontinuously formed.

Si is deposited on the wafer 200 to form the silicon layer including Clunder the conditions in which the HCDS gas is autolyzed (pyrolyzed),i.e., the conditions in which a pyrolysis reaction of the HCDS isgenerated. The HCDS gas is adsorbed onto the wafer 200 to form theadsorption layer of the HCDS gas under the conditions in which the HCDSgas is not autolyzed (pyrolyzed), i.e., the conditions in which apyrolysis reaction of the HCDS is not generated. In addition, afilm-forming rate may be higher when the silicon layer including Cl isformed on the wafer 200 than when the adsorption layer of the HCDS gasis formed on the wafer 200.

When the thickness of the silicon-containing layer including Cl formedon the wafer 200 exceeds several atomic layers, an effect ofmodification in the following step 2 and step 3 is not delivered to theentire silicon-containing layer including Cl. In addition, a minimumvalue of the thickness of the silicon-containing layer including Cl tobe formed on the wafer 200 is less than one atomic layer. Accordingly,the thickness of the silicon-containing layer including Cl may be lessthan one atomic layer to about several atomic layers. Further, when thethickness of the silicon-containing layer including Cl is one atomiclayer or less, i.e., one atomic layer or less than one atomic layer, theeffect of the modification reaction in the following step 2 and step 3can be relatively improved, and a time needed for the modificationreaction in steps 2 and 3 can be reduced. A time needed to form thesilicon-containing layer including Cl in step 1 can also be reduced.Eventually, a processing time per cycle can be reduced, thereby reducinga total processing time. That is, the film-forming rate can also beincreased. In addition, when the thickness of the silicon-containinglayer including Cl is one atomic layer or less, controllability of thefilm thickness uniformity can also be increased.

Remaining Gas Removal

After the silicon-containing layer including Cl is formed as a seedlayer, the valve 243 a of the first gas supply pipe 232 a is closed tostop supply of the HCDS gas. Here, the inside of the process chamber 201is vacuum-exhausted by the vacuum pump 246 in a state in which the APCvalve 244 of the exhaust pipe 231 is open (preferably, in a state inwhich the APC valve 244 is fully open), and the HCDS gas afternon-reaction or contribution to formation of the seed layer andremaining in the process chamber 201 is removed from the inside of theprocess chamber 201. In this case, supply of the N₂ gas, which is aninert gas, into the process chamber 201 is maintained in a state inwhich the valves 243 e, 243 f, and 243 g are open. The N₂ gas serves asa purge gas, and thus an effect of removing the HCDS gas afternon-reaction or contribution to formation of the seed layer andremaining in the process chamber 201 from the inside of the processchamber 201 can be increased.

In addition, here, the gas remaining in the process chamber 201 may notbe completely removed, and the inside of the process chamber 201 may notbe completely purged. When the gas remaining in the process chamber 201is minute, there is no bad influence on step 2 performed thereafter.Here, a flow rate of the N₂ gas supplied into the process chamber 201need not be a large flow rate, and for example, an amount of N₂ gassubstantially equal to a capacity of the reaction tube 203 (the processchamber 201) may be supplied to perform the purge such that no badinfluence is generated in step 2. As described above, as the inside ofthe process chamber 201 is not completely purged, the purge time can bereduced to improve throughput. In addition, consumption of the N₂ gascan be suppressed to a necessary minimum value.

In addition to hexachlorodisilane (Si₂Cl₆, abbreviated to HCDS) gas, aninorganic source gas such as tetrachlorosilane, i.e.,silicontetrachloride (SiCl₄, abbreviated to STC) gas, trichlorosilane(SiHCl₃, abbreviated to TCS) gas, dichlorosilane (SiH₂Cl₂, abbreviatedto DCS) gas, monochlorosilane (SiH₃Cl, abbreviated to MCS) gas, or thelike, may be used as the chlorosilane-based source gas. In addition tothe N₂ gas, a rare gas such as Ar gas, He gas, Ne gas, Xe gas, or thelike may be used as the inert gas.

Step 2

TEA Gas Supply

After step 1 is terminated and the remaining gas in the process chamber201 is removed, the valve 243 b of the second gas supply pipe 232 b isopened to cause the TEA gas to flow through the second gas supply pipe232 b. The flow rate of the TEA gas flowing through the second gassupply pipe 232 b is controlled by the mass flow controller 241 b. Theflow-rate-controlled TEA gas is supplied into the process chamber 201through the gas supply hole 250 b of the second nozzle 249 b. The TEAgas supplied into the process chamber 201 is thermally activated(excited) to be exhausted through the exhaust pipe 231. Here, thethermally activated TEA gas is supplied to the wafer 200.Simultaneously, the valve 243 f is opened to cause the N₂ gas, which isan inert gas, to flow through the second inert gas supply pipe 232 f.The flow rate of the N₂ gas flowing through the second inert gas supplypipe 232 f is controlled by the mass flow controller 241 f. Theflow-rate-controlled N₂ gas is supplied into the process chamber 201 tobe exhausted through the exhaust pipe 231, together with the TEA gas.

In addition, here, in order to prevent invasion of the TEA gas into thefirst nozzle 249 a and the third nozzle 249 c, the valves 243 e and 243g are opened to cause the N₂ gas to flow through the first inert gassupply pipe 232 e and the third inert gas supply pipe 232 g. The N₂ gasis supplied into the process chamber 201 via the first gas supply pipe232 a, the third gas supply pipe 232 c, the first nozzle 249 a and thethird nozzle 249 c, and is exhausted through the exhaust pipe 231.

The TEA gas can be supplied to the wafer 200 to react thesilicon-containing layer including Cl, which is a seed layer formed onthe wafer 200 in step 1, under the above-mentioned conditions. That is,atoms (Cl atoms) of a halogen element included in the silicon-containinglayer including Cl, which is a seed layer, can be reacted with ligands(ethyl groups) included in the TEA gas. Accordingly, as at least some Clincluded in the seed layer is drawn (separated) from the seed layer, andsimultaneously, at least some ethyl groups of the plurality of ethylgroups included in the TEA gas can be separated from the TEA gas. Then,N of the TEA gas from which at least some ethyl groups are separated canbe bonded to Si included in the seed layer. That is, N forming the TEAgas, from which at least some ethyl groups are separated, and includingdangling bonds, can be bonded to Si included in the seed layer includingdangling bonds, or Si that includes the dangling bonds, forming Si—Nbonds. In addition, here, C included in the ethyl group (—CH₂CH₃)separated from the TEA gas can be bonded to Si included in the seedlayer, thereby forming Si—C bonds. As a result, Cl is desorbed from theseed layer, and a N component is newly introduced into the seed layer.In addition, here, a C component is also newly introduced into the seedlayer.

Since the TEA gas can be supplied to appropriately react thesilicon-containing layer including Cl, which is a seed layer, with theTEA gas under the above-mentioned conditions, the series of reactionsdescribed above can be generated.

The N component and the C component are newly introduced into the seedlayer while Cl is desorbed from the seed layer by the series ofreactions, and the silicon-containing layer including Cl, which is aseed layer, is changed (modified) into the first layer including silicon(Si), nitrogen (N) and carbon (C), i.e., the silicon carbonitride (SiCN)layer. The first layer becomes a layer including Si, N and C and havinga thickness of less than one atomic layer to several atomic layers. Inaddition, the first layer becomes a layer having a relatively high ratioof a Si component and a C component, i.e., a Si-rich or C-rich layer.

In addition, when a layer including Si, N, and C is formed as the firstlayer, chlorine (Cl) included in the silicon-containing layer includingCl and hydrogen (H) included in the TEA gas composes a gaseous material,such as chlorine (Cl₂) gas, hydrogen (H₂) gas, or hydrogen chloride(HCl) gas, and is discharged from the inside of the process chamber 201via the exhaust pipe 231 during a modification reaction of thesilicon-containing layer including Cl by the TEA gas. That is,impurities, such as Cl or the like, in the seed layer are drawn ordesorbed from the seed layer to be separated from the seed layer.Accordingly, the first layer becomes a layer having a smaller amount ofimpurities such as Cl or the like than the seed layer.

In addition, in step 2, the flow rate of the TEA gas, the flow rate ofthe N₂ gas, and the pressure in the process chamber 201 are controlledby the mass flow controller 241 b, the mass flow controller 241 f, andthe APC valve 244 as illustrated in FIG. 8. FIG. 8 illustrates therelationship among the flow rate of the reactive gas (TEA gas), the flowrate of the inert gas (N₂ gas), the pressure in the process chamber 201,and the degree of opening of the exhaust valve (APC valve) in step 2,i.e., the process of the reactive gas (TEA gas).

When the TEA gas is supplied in step 2, first, the TEA gas is suppliedat the first flow rate (first TEA gas supply process). Then, after thepressure in the process chamber 201 reaches a predetermined pressure,the TEA gas is supplied at the second flow rate that is less than thefirst flow rate while maintaining the pressure in the process chamber201 (second TEA gas supply process). In other words, in step 2, duringthe supply of the TEA gas, the TEA gas is initially supplied at acomparatively high flow rate, and the flow rate of the TEA gas islowered after a predetermined time and in a stable state in which thepressure in the process chamber 201 reaches a predetermined pressure,while maintaining the predetermined pressure in the process chamber 201.In this case, in step 2, a total supply rate of the TEA gas into theprocess chamber 201, i.e., a consumption rate of the TEA gas, may belowered more than when the TEA gas is supplied at the first flow rateinto the process chamber 201.

In addition, the degree of opening of the APC valve 244 installed at anexhaust line configured to exhaust the inside of the process chamber 201may be set to a first degree of opening when the TEA gas is supplied atthe first flow rate, and may be set to be a second degree of opening(which is greater (wider) than the first degree of opening) when the TEAgas is supplied at the second flow rate. That is, an exhaust conductanceat an exhaust line configured to exhaust the inside of the processchamber 201 may be set to be a first exhaust conductance, and when theTEA gas is supplied at the second flow rate, may be set to be a secondexhaust conductance that is greater than the first exhaust conductancewhen the TEA gas is supplied at the first flow rate. In other words,when the TEA gas is supplied at the first flow rate, the degree ofopening of the APC valve 244 may be set to be the first degree ofopening that is less (narrower) than the second degree of opening andthe exhaust conductance may be set to be the first exhaust conductancethat is less than the second exhaust conductance. In this case, when theTEA gas is supplied at the first flow rate, a total flow rate of gasessupplied into the process chamber 201 (i.e., the sum of the flow rate ofthe TEA gas and the flow rate of the N₂ gas) may be greater than anexhaust flow rate of a gas exhausted via the exhaust line. In this case,the pressure in the process chamber 201 may be rapidly raised and maythus be regulated to a predetermined pressure within a short timeperiod. That is, a time needed to regulate the process chamber 201 tothe predetermined pressure may be shortened. In addition, since thepressure in the process chamber 201 may be rapidly raised to acomparatively high pressure, the amount of carbon (C) present in theprocess chamber 201 may be increased, the amount of carbon (C) added tothe first layer may be increased, and the concentration of carbon (C)contained in the first layer may be increased. The second degree ofopening means a degree of opening that allows the pressure in theprocess chamber 201 to be maintained at a predetermined level and thatis automatically adjusted by the controller 121 as illustrated in FIG.8. The second exhaust conductance means a conductance that allows thepressure in the process chamber 201 to be maintained at a predeterminedlevel and that is automatically adjusted by controlling the APC valve244 via the controller 121.

In addition, the degree of opening (first degree of opening) of the APCvalve 244 installed at the exhaust line configured to exhaust the insideof the process chamber 201 is fully closed to suspend controlling of thedegree of opening of the APC valve 244 (feedback control) when the TEAgas is supplied at the first flow rate, and may be opened to control thedegree of opening of the APC valve 244 when the TEA gas is supplied atthe second flow rate. That is, the exhaust line configured to exhaustthe inside of the process chamber 201 may be blocked when the TEA gas issupplied at the first flow rate, and may be opened when the TEA gas issupplied at the second flow rate. In this case, a total flow rate ofgases supplied into the process chamber 201 (i.e., the sum of the flowrates of the TEA gas and the N₂ gas) when the TEA gas is supplied at thefirst flow rate is greater than the exhaust flow rate of a gas exhaustedvia the exhaust line. In addition, the difference between the total flowrate and the exhaust flow rate is maximized. Thus, the pressure in theprocess chamber 201 may be more rapidly raised to be regulated to apredetermined pressure within a shorter time period. That is, a timeneeded to regulate the pressure in the process chamber 201 to thepredetermined pressure may be shortened more. In addition, since thepressure in the process chamber 201 may be more rapidly raised to a highpressure, the amount of carbon (C) present in the process chamber 201may be increased more, the amount of carbon (C) added to the first layermay be increased more, and the concentration of carbon (C) contained inthe first layer may be increased more.

In addition, the degree of opening (first degree of opening) of the APCvalve 244 installed at the exhaust line configured to exhaust the insideof the process chamber 201 may not be fully closed when the TEA gas issupplied at the first flow rate. For example, the APC valve 244 may beslightly opened to control the degree of opening of the APC valve 244.That is, when the TEA gas is supplied at the first flow rate, a fine gasflow may be formed from the inside of the process chamber 201 toward thevacuum pump 246 by slightly opening the APC valve 244 (by extremelyreducing (narrowing) the first degree of opening) without adjusting thefirst exhaust conductance to zero. Even in this case, the total flowrate of gases supplied into the process chamber 201 may also be adjustedto be greater than the exhaust flow rate of a gas exhausted via theexhaust line. In this case, this state in which the total flow rate ofgases supplied into the process chamber 201 is greater than the exhaustflow rate of gas exhausted via the exhaust line may be caused bycontrolling flow rate adjustment and pressure regulation by the massflow controllers 241 b and 241 f and the APC valve 244 through thecontroller 121, respectively. In this case, the pressure in the processchamber 201 may also be rapidly raised to the predetermined pressure andthe concentration of carbon (C) contained in the first layer may also beincreased. However, the pressure in the process chamber 201 may be morerapidly raised and the concentration of carbon (C) contained in thefirst layer may be more increased when the degree of opening (firstdegree of opening) of the APC valve 244 is fully closed.

In addition, the pressure in the process chamber 201 is changedaccording to a balance between the flow rate of a gas supplied into theprocess chamber 201 and the exhaust speed (exhaust conductance) of a gasexhausted by the exhaust line configured to exhaust the inside of theprocess chamber 201. Since it may take a time to stabilize this balance,the pressure in the process chamber 201 may not be raised to thepredetermined pressure within a short time period while exhausting isperformed using the exhaust line, thereby lowering product yield. Inparticular, when the flow rate of a gas supplied into the processchamber 201 is lowered, it may take a time to raise the pressure in theprocess chamber 201, thereby greatly lowering product yield. Incontrast, according to the first embodiment, when the TEA gas issupplied at the first flow rate, the degree of opening (first degree ofopening) of the APC valve 244 installed at the exhaust line is fullyclosed, the APC valve 244 is slightly opened (first degree of opening islowered), or the degree of opening (first degree of opening) of the APCvalve 244 is set to be less than the second degree of opening. Thus, thepressure in the process chamber 201 may be raised within a short timeperiod and the film-forming yield may be improved, thereby increasingthe concentration of carbon (C) contained in the first layer.

In addition, N₂ gas may be supplied at a third flow rate when the TEAgas is supplied at the first flow rate, and may be supplied at a fourthflow rate that is less than the third flow rate when the TEA gas issupplied at the second flow rate. That is, when the flow rate of the TEAgas supplied into the process chamber 201 is lowered, the flow rate ofthe N₂ gas supplied into the process chamber 201 may also be lowered. Inthis case, partial pressure of the TEA gas, i.e., the concentration ofthe TEA gas in the process chamber 201, may be prevented from beinglowered in the process chamber 201 after the flow rate of the TEA gassupplied into the process chamber 201 is lowered. In addition, an actualsupply rate of the TEA gas to the wafer 200, i.e., the number of TEAmolecules supplied to the wafer 200, may be suppressed from beingreduced. That is, the partial pressure and concentration of the TEA gasand the number of TEA molecules supplied to the wafer 200 when the TEAgas is supplied at the first flow rate and the pressure in the processchamber 201 reaches the predetermined pressure may be maintainedconstant even after the flow rate of the TEA gas supplied into theprocess chamber 201 is lowered. As a result, the amount of carbon (C)added to the first layer, i.e., the concentration of carbon (C)contained in the first layer, may be suppressed from being lowered.

In addition, in step 2 (TEA gas supply process), i.e., during the firstTEA gas supply process and the second TEA gas supply process, the ratioof the flow rate of the TEA gas to that of the N₂ gas supplied into theprocess chamber 201 is preferably maintained constant. That is, when theflow rates of the TEA gas and the N₂ gas supplied into the processchamber 201 are lowered to the second and fourth flow rates,respectively, the ratio of the first flow rate to the third flow rateand the ratio of the second flow rate to the fourth flow rate arepreferably set to be the same. That is, the second flow rate and thefourth flow rate may be set to satisfy (first flow rate:third flowrate=second flow rate:fourth flow rate). In other words, in step 2, theratio (percentage) of the flow rate of the TEA gas to the sum of theflow rates of the TEA gas and the N₂ gas, i.e., the rate of the TEA gas(percentage), is preferably maintained constant. That is, the flow rateof the TEA gas/(the flow rate of the TEA gas+the flow rate of the N₂gas) is preferably maintained constant. That is, when the flow rates ofthe TEA gas and the N₂ gas supplied into the process chamber 201 arelowered to the second flow rate and the fourth flow rate, respectively,the second flow rate and the fourth flow rate are preferably set tosatisfy that (first flow rate/(first flow rate+third flow rate))=(secondflow rate/(second flow rate+fourth flow rate)).

The partial pressure V_(T)(Pa) of the TEA gas in the process chamber 201may be expressed as an equation: VT=[Q_(T)/(Q_(T)+Q_(N))]×V when theflow rate of the TEA gas supplied into the process chamber 201 isQ_(T)(sccm), the flow rate of the N₂ gas supplied into the processchamber 201 is Q_(N)(sccm), and the total pressure in the processchamber 201 is V(Pa). Thus, if the flow rates of the TEA gas and the N₂gas supplied into the process chamber 201 are lowered to the second flowrate and the fourth flow rate, respectively, then the partial pressureV_(T) of the TEA gas in the process chamber 201 is maintained constantwhen the second flow rate and the fourth flow rate are set to maintainthe rate of the TEA gas, i.e., [Q_(T)/(Q_(T)+Q_(N))], constant. That is,the partial pressure V_(T) of the TEA gas in the process chamber 201 maybe maintained constant by maintaining the rate of the TEA gas[=Q_(T)/(Q_(T)+Q_(N))] constant while maintaining the pressure in theprocess chamber 201 at a predetermined pressure V, at least after thepressure in the process chamber 201 reaches a predetermined pressure V.As a result, an actual supply state of the TEA gas with respect to thewafer 200 may be maintained constant both before and after the flow rateof the TEA gas is lowered. That is, the number of TEA molecules suppliedto the wafer 200 may be maintained constant both before and after theflow rate of the TEA gas is lowered. Accordingly, after the flow rate ofthe TEA gas is lowered, the amount of carbon (C) added to the firstlayer, i.e., the concentration of carbon (C) contained in the firstlayer, may be suppressed from being lowered.

In addition, in step 2 (TEA gas supply process), the amount of carbon(C) added to the first layer may be changed by changing the ratio of theflow rate of the TEA gas to that of the N₂ gas supplied into the processchamber 201 when the flow rate of the TEA gas supplied into the processchamber 201 is lowered, i.e., by changing the partial pressure in theprocess chamber 201. For example, when the flow rate of the TEA gassupplied into the process chamber 201 is lowered, the amount of carbon(C) added to the first layer may be reduced by adjusting the flow rateof the N₂ gas to satisfy (fourth flow rate)>(third flow rate)_(x)(secondflow rate)/(first flow rate), i.e., by lowering the partial pressure ofthe TEA gas in the process chamber 201 by reducing the rate of the TEAgas. In addition, for example, when the flow rate of the TEA gassupplied into the process chamber 201 is lowered, the amount of carbon(C) added to the first layer may be reduced by adjusting the flow rateof the N₂ gas to satisfy (fourth flow rate)<(third flow rate)_(x)(secondflow rate)/(first flow rate), i.e., by increasing the partial pressureof the TEA gas in the process chamber 201 by increasing the rate of theTEA gas.

In addition, when the TEA gas is supplied at the first flow rate, thepressure in the process chamber 201 may be set to fall within, forexample, a range of 1 to 13,300 Pa, and preferably, a range of 399 to3,990 Pa. When the pressure in the process chamber 201 is set to becomparatively high, the TEA gas may be thermally activated in anon-plasma state. In addition, since the TEA gas may be thermallyactivated and supplied to cause a soft reaction, the modificationdescribed above may be softly performed. The supply flow rate of the TEAgas may be controlled to be within, for example, a range of 200 to 4,000sccm using by the mass flow controller 241 b. The supply flow rate ofthe N₂ gas may be controlled to be within, for example, a range of 200to 10,000 sccm using each of the mass flow controllers 241 f, 241 e, and241 g. In this case, the partial pressure of the TEA gas in the processchamber 201 is controlled to be within a range of 0.02 to 12,667 Pa. Atime period in which the thermally activated TEA gas is supplied to thewafer 200, i.e., a gas supply time (exposure time), may be, for example,within a range of 6 to 24 seconds. In this case, similar to step 1, thetemperature of the heater 207 is set such that the temperature of thewafer 200 may be, for example, within a range of 250 to 700° C.,preferably, 300 to 650° C., and more preferably, 350 to 600° C.

When the TEA gas is supplied at the second flow rate, the pressure inthe process chamber 201 may be, for example, within a range of 1 to13,300 Pa, and preferably, a range of 399 to 3,990 Pa, similar to whenthe TEA gas is supplied at the first flow rate. The supply flow rate ofthe TEA gas controlled by the mass flow controller 241 b may be, forexample, within a range of 100 to 2,000 sccm. The supply flow rate ofthe N₂ gas controlled by the mass flow controllers 241 f, 241 e, and 241g may be, for example, within a range of 100 to 5,000 sccm. In thiscase, the partial pressure of the TEA gas in the process chamber 201 maybe within a range of 0.02 to 12,667 Pa, similar to when the TEA gas issupplied at the first flow rate. A time period in which the thermallyactivated TEA gas is supplied to the wafer 200, i.e., a gas supply time(exposure time), may be, for example, within a range of 12 to 120seconds. In this case, similar to step 1, the temperature of the heater207 is set such that the temperature of the wafer 200 may be, forexample, within a range of 250 to 700° C., preferably, 300 to 650° C.,and more preferably, 350 to 600° C., similar to when the TEA gas issupplied at the first flow rate.

Remaining Gas Removal

After the first layer is formed, the valve 243 b of the second gassupply pipe 232 b is closed and the supply of the TEA gas is suspended.In this case, the inside of the process chamber 201 is vacuum-exhaustedby the vacuum pump 246 in a state in which the APC valve 244 of theexhaust pipe 231 is opened (preferably, in a state in which the APCvalve 244 is fully opened), and either the TEA gas remaining in theprocess chamber 201 after non-reaction or contribution to formation ofthe first layer or reaction byproducts are removed from the inside ofthe process chamber 201. In addition, in this case, supply of N₂ gas asan inert gas into the process chamber 201 is maintained while the valves243 f, 243 e, and 243 g are opened. The N₂ gas serves as a purge gas,and causes either the TEA gas remaining in the process chamber 201 afternon-reaction or contribution to formation of the first layer or thereaction byproducts to be effectively removed from the inside of theprocess chamber 201.

In this case, a gas remaining in the process chamber 201 may not becompletely removed and the inside of the process chamber 201 may not becompletely purged. When a small amount of the gas is remained in theprocess chamber 201, step 3 performed after step 2 is not badlyinfluenced by this gas. In this case, the flow rate of the N₂ gas to besupplied into the process chamber 201 may not be high. For example, theinside of the process chamber 201 may be purged by supplying an amountof N₂ gas corresponding to the capacity of the reaction tube 203(process chamber 201) such that step 3 is not badly influenced by thisgas. As described above, a purge time may be shortened by not completelypurging the inside of the process chamber 201, thereby improving thethroughput. In addition, consumption of the N₂ gas may be suppressed toa necessary minimum value.

As an amine-based gas, not only triethylamine [(C₂H₅)₃N, abbreviated toTEA] but also an ethylamine-based gas obtained by evaporatingdiethylamine [(C₂H₅)₂NH, abbreviated to DEA], monoethylamine (C₂H₅NH₂,abbreviated to MEA) or the like; a methylamine-based gas obtained byevaporating trimethylamine [(CH₃)₃N, abbreviated to TMA], dimethylamine[(CH₃)₂NH, abbreviated to DMA], monomethylamine (CH₃NH₂, abbreviated toMMA), or the like; a propylamine-based gas obtained by evaporatingtripropylamine [(C₃H₇)₃N, abbreviated to TPA], dipropylamine [(C₃H₇)₂NH,abbreviated to DPA], monopropylamine (C₃H₇NH₂, abbreviated to MPA), orthe like; an isopropyl amine-based gas obtained by evaporatingtriisopropylamine [(CH₃)₂CH]₃N, abbreviated to TIPA), diisopropylamine[(CH₃)₂CH]₂NH, abbreviated to DIPA), monoisopropylamine [(CH₃)₂CHNH₂,abbreviated to MIPA), or the like; a butyl-based gas obtained byevaporating tributylamine [(C₄H₉)₃N, abbreviated to TBA], dibutylamine[(C₄H₉)₂NH, abbreviated to DBA], monobutylamine (C₄H₉NH₂, abbreviated toMBA), or the like; or an isobutylamine-based gas obtained by evaporatingtriisobutylamine [(CH₃)₂CHCH₂]₃N, abbreviated to TIBA), diisobutylamine([(CH₃)₂CHCH₂]₂NH, abbreviated to DIBA), monoisobutylamine[(CH₃)₂CHCH₂NH₂, abbreviated to MIBA] or the like may be used.

That is, for example, at least one gas among (C₂H₅)_(x)NH_(3-x),(CH₃)_(x)NH_(3-x), (C₃H₇)_(x)NH_(3-x), [(CH₃)₂CH]_(x)NH_(3-x),(C₄H₉)_(x)NH_(3-x), and [(CH₃)₂CHCH₂]_(x)NH_(3-x) may be preferably usedas an amine-based gas. Here, ‘x’ denotes an integer between 1 and 3.

In addition, as the amine-based gas, a gas consisting of three elements,such as carbon, nitrogen, and hydrogen, and having a composition ratioin which the number of carbon atoms is greater than the number ofnitrogen atoms (in one molecule). That is, at least one gas containingan amine selected from the group consisting of TEA, DEA, MEA, TMA, DMA,TPA, DPA, MPA, TIPA, DIPA, MIPA, TBA, DBA, MBA, TIBA, DIBA, and MIBA ispreferably used as the amine-based gas.

If a chlorosilane-based source gas, e.g., the HCDS gas that contains aspecific element (silicon) and a halogen element (chlorine), is used asa source gas, then an amine-based gas consisting of three elements, suchas carbon, nitrogen, and hydrogen, and having a composition ratio inwhich the number of carbon elements is greater than the number ofnitrogen elements (in one molecule), e.g., the TEA gas or the DEA gas,may be used as the first reactive gas in order to increase theconcentration of carbon in the first layer formed in step 2, that is,the concentration of carbon in a SiOCN film or a SiOC film to be formedduring a process performed a predetermined number of times (to bedescribed later).

In contrast, if a chlorosilane-based source gas, e.g., the HCDS gas thatcontains a specific element (silicon) and a halogen element (chlorine),is used as a source gas, when an amine-based gas, such as MMA gas, or anorganic hydrazine-based gas, such as MMH gas or DMH gas consisting ofthree elements, such as carbon, nitrogen, and hydrogen, and having acomposition ratio in which the number of carbon atoms is not greaterthan the number of nitrogen atoms (in one molecule) (which will bedescribed below), is used as the first reactive gas, then theconcentration of carbon in the first layer, i.e., the concentration ofcarbon in the SiOCN film or the SiOC film, is less than when anamine-based gas consisting of three elements, such as carbon, nitrogen,and hydrogen, and having a composition ratio in which the number ofcarbon atoms is greater than the number of nitrogen atoms (in onemolecule) is used as the first reactive gas. Accordingly, an appropriateconcentration of carbon cannot be achieved.

In addition, a gas having a composition ratio in which a plurality ofligands containing carbon atoms are contained (in one molecule), i.e., agas having a composition ratio in which a plurality of hydrocarbongroups (e.g., alkyl groups) are contained (in one molecule), ispreferably used as an amine-based gas. In detail, a gas having acomposition ratio in which two or three ligands (hydrocarbon groups,such as alkyl groups) containing carbon elements are contained (in onemolecule), is preferably used as the amine-based gas. For example, atleast one gas containing an amine selected from the group consisting ofTEA, DEA, TMA, DMA, TPA, DPA, TIPA, DIPA, TBA, DBA, TIBA, and DIBA ispreferably used.

If a chlorosilane-based source gas, such as the HCDS gas containing aspecific element (silicon) and a halogen element (chlorine), is used asa source gas, an amine-based gas (such as the TEA gas or the DEA gas)that consists of three elements, such as carbon, nitrogen, and hydrogen,and has a composition ratio in which a plurality of ligands containingcarbon atoms are contained (in one molecule), i.e., an amine-based gashaving a composition ratio in which a plurality of hydrocarbon groups(alkyl groups) are contained in one molecule, may be used as the firstreactive gas in order to increase the concentration of carbon in thefirst layer, that is, the concentration of carbon in the SiOCN film orthe SiOC film.

In contrast, if a chlorosilane-based source gas, e.g., the HCDS gas thatcontains a specific element (silicon) and a halogen element (chlorine),is used as a source gas, when an amine-based gas such as MMA gas or anorganic hydrazine-based gas such as the MMH gas (which will be describedbelow), which has a composition ratio in which a plurality of ligandscontaining carbon are not contained (in one molecule) (which will bedescribed below), is used as the first reactive gas, then theconcentration of carbon in the first layer, i.e., the concentration ofcarbon in the SiOCN film or the SiOC film, is less than when anamine-based gas having a composition ratio in which a plurality ofligands containing carbon are contained (in one molecule) is used as thefirst reactive gas. Accordingly, an appropriate concentration of carboncannot be achieved.

In addition, when an amine-based gas (e.g., DEA gas) having acomposition ratio in which two ligands containing carbon atoms(hydrocarbon groups such as alkyl groups) are contained (in onemolecule) is used as the first reactive gas, a cycle rate (thickness ofa SiOCN layer or a SiOC layer formed per unit cycle) may be improvedmore and the ratio of the concentration of nitrogen to the concentrationof carbon (nitrogen concentration/carbon concentration) in the firstlayer, i.e., the ratio of the concentration of nitrogen to theconcentration of carbon (nitrogen concentration/carbon concentration) inthe SiOCN film or the SiOC film, may be higher than when an amine-basedgas (e.g., TEA gas) having a composition ratio in which three ligandscontaining carbon atoms (hydrocarbon groups such as alkyl groups) arecontained (in one molecule) is used.

In contrast, when an amine-based gas (e.g., TEA gas) having acomposition ratio in which three ligands containing carbon atoms(hydrocarbon groups such as alkyl groups) are contained (in onemolecule) is used as the first reactive gas, the ratio of theconcentration of carbon to the concentration of nitrogen (carbonconcentration/nitrogen concentration) in the first layer, i.e., theratio of the concentration of carbon to the concentration of nitrogen(carbon concentration/nitrogen concentration) in the SiOCN film or theSiOC film may be higher than when an amine-based gas (e.g., DEA gas)having a composition ratio in which two ligands containing carbon atoms(hydrocarbon groups such as alkyl groups) are contained (in onemolecule) is used.

That is, a cycle rate or the concentration of nitrogen or carbon in theSiOCN film or the SiOC film to be formed may be finely controlled byappropriately adjusting a gas species of the first reactive gasaccording to the number of ligands containing carbon atoms (the numberof hydrocarbon groups such as alkyl groups) in the first reactive gas.

Gas specifies (composition) of an amine-based gas serving as a firstreactive gas may be appropriately selected to increase the concentrationof carbon in the SiOCN film or the SiOC film as described above.However, in order to more increase the concentration of carbon, forexample, the pressure in the process chamber 201 when an amine-based gas(TEA gas) is supplied to the wafer 200 is preferably higher than thepressure in the process chamber 201 when a chlorosilane-based source gas(HCDS gas) is supplied to the wafer 200 (in step 1), and is preferablyhigher than the pressure in the process chamber 201 when anoxygen-containing gas (O₂ gas) is supplied to the wafer 200 (in step 3which will be described below). In addition, in this case, the pressurein the process chamber 201 when the O₂ gas is supplied to the wafer 200(in step 3) is preferably higher than the pressure in the processchamber 201 when the HCDS gas is supplied to the wafer 200 (in step 1).That is, if the pressure in the process chamber 201 when the HCDS gas issupplied to the wafer 200 is P₁ [Pa], the pressure in the processchamber 201 when the TEA gas is supplied to the wafer 200 is P₂ [Pa],and the pressure in the process chamber 201 when the O₂ gas is suppliedto the wafer 200 P₃ [Pa], the pressures P₁ to P₃ are preferably set tosatisfy P₂>P₁, P₃ and are more preferably set to satisfy P₂>P₃>P₁. Inother words, the pressure in the process chamber 201 when the TEA gas issupplied to the wafer 200 is preferably highest among those in steps 1to 3.

In contrast, in order to appropriately suppress an increase in theconcentration of carbon in the SiOCN film or the SiOC film, the pressurein the process chamber 201 when an amine-based gas (TEA gas) is suppliedto the wafer 200 is preferably less than or equal to the pressure in theprocess chamber 201 when an oxygen-containing gas (O₂ gas) is suppliedto the wafer 200 in step 3 or the pressure in the process chamber 201when a chlorosilane-based source gas (HCDS gas) is supplied to the wafer200 in step 1. That is, the pressures P₁ to P₃ are preferably set tosatisfy P₃≧P₂ or P₃, P₁≧P₂.

That is, the pressure in the process chamber 201 when the amine-basedgas is supplied may be appropriately controlled to finely adjust thecarbon concentration in the SiOCN film or the SiOC film.

In addition to N₂ gas, a rare gas such as Ar gas, He gas, Ne gas, Xegas, or the like, may be used as the inert gas.

Step 3

O₂ Gas Supply

After step 2 is terminated and the remaining gas in the process chamber201 is removed, the valve 243 c of the third gas supply pipe 232 c isopened to cause O₂ gas to flow through the third gas supply pipe 232 c.The flow rate of the O₂ gas flowing through the third gas supply pipe232 c is controlled by the mass flow controller 241 c. Theflow-rate-controlled O₂ gas is supplied into the process chamber 201 viathe gas supply hole 250 c of the third nozzle 249 c. The O₂ gas suppliedinto the process chamber 201 is thermally activated (excited) to beexhausted through the exhaust pipe 231. Here, the thermally activated O₂gas is supplied to the wafer 200. Simultaneously, the valve 243 g isopened to cause N₂ gas to flow through the third inert gas supply pipe232 g. The N₂ gas is supplied into the process chamber 201 to beexhausted through the exhaust pipe 231 with the O₂ gas. In addition,here, in order to prevent invasion of the O₂ gas into the first nozzle249 a and the second nozzle 249 b, the valves 243 e and 243 f are openedto cause the N₂ gas to flow through the first inert gas supply pipe 232e and the second inert gas supply pipe 232 f. The N₂ gas is suppliedinto the process chamber 201 via the first gas supply pipe 232 a, thesecond gas supply pipe 232 b, the first nozzle 249 a, and the secondnozzle 249 b to be exhausted through the exhaust pipe 231.

Here, the APC valve 244 is appropriately adjusted such that the pressurein the process chamber 201 is a pressure within a range of, for example,1 to 3,000 Pa. As the pressure in the process chamber 201 arrives atsuch a relatively high pressure, the O₂ gas can be thermally activatedwith non-plasma. In addition, since the O₂ gas may be thermallyactivated to be supplied to generate a soft reaction, oxidation (to bedescribed below) may be softly performed. A supply flow rate of the O₂gas controlled by the mass flow controller 241 c is a flow rate within arange of, for example, 100 to 10,000 sccm. A supply flow rate of the N₂gas controlled by the mass flow controllers 241 g, 241 e and 241 f maybe a flow rate within a range of, for example, 100 to 10,000 sccm. Here,a partial pressure of the O₂ gas in the process chamber 201 is apressure within a range of 0.01 to 2,970 Pa. A time in which thethermally activated O₂ gas is supplied to the wafer 200, i.e., a gassupply time (exposure time), is a time within a range of for example, 1to 120 seconds, preferably 1 to 60 seconds. Here, like steps 1 and 2,the temperature of the heater 207 is set such that the temperature ofthe wafer 200 is a temperature within a range of, for example, 250 to700° C., preferably 300 to 650° C., and more preferably 350 to 600° C.

Here, the gas flowing into the process chamber 201 is the O₂ gasthermally activated by increasing the pressure in the process chamber201, and neither HCDS gas nor TEA gas flows into the process chamber201. Accordingly, the O₂ gas does not generate a gaseous reaction, andthe activated O₂ gas reacts with at least a portion of the first layerincluding Si, N and C formed on the wafer 200 in step 2. Accordingly,the first layer is oxidized to be modified as a layer including silicon,oxygen, carbon, and nitrogen, which is a second layer, i.e., a siliconoxycarbonitride layer (SiOCN layer), or a layer including silicon,oxygen and carbon, i.e., a silicon oxycarbide layer (SiOC layer).

In addition, as the O₂ gas is thermally activated to be flowed into theprocess chamber 201, the first layer may be thermally oxidized to bemodified (changed) into the SiOCN layer or the SiOC layer. Here, an Ocomponent is added to the first layer to modify the first layer into theSiOCN layer or the SiOC layer. In addition, the Si—O bonding in thefirst layer is increased by an action of the thermal oxidation due tothe O₂ gas, and the Si—N bonding, Si—C bonding, and Si—Si bonding arereduced to reduce a ratio of an N component, a ratio of a C component,and a ratio of a Si component in the first layer. In addition, here, asthe thermal oxidation time is lengthened or an oxidizing power of thethermal oxidation is increased, most of the N component can be desorbedto reduce the N component to an impurity level or substantially removethe N component. That is, the first layer may be modified into the SiOCNlayer or the SiOC layer while varying the composition ratio thereof in adirection of increasing the oxygen concentration or in a direction ofreducing the nitrogen concentration, the carbon concentration and thesilicon concentration. In addition, here, the process conditions such asthe pressure in the process chamber 201, the gas supply time, or thelike, may be controlled to finely adjust a ratio of the O component inthe SiOCN layer or the SiOC layer, i.e., the oxygen concentration, andthe composition ratio of the SiOCN layer or the SiOC layer may thus bemore finely controlled.

In addition, it has been confirmed that the C component is richer thanthe N component in the first layer formed in steps 1 and 2. For example,in an experiment, the carbon concentration was twice the nitrogenconcentration or more. That is, as the oxidation is blocked before the Ncomponent in the first layer is completely desorbed by an action of thethermal oxidation due to the O₂ gas, i.e., in a state in which the Ncomponent remains, the C component and the N component remain in thefirst layer so that the first layer is modified into the SiOCN layer. Inaddition, the C component remains in the first layer even in a step inwhich most of the N component in the first layer is desorbed by theaction of the thermal oxidation due to the O₂ gas, and in this state,the oxidation is blocked so that the first layer is modified into theSiOC layer. That is, the gas supply time (oxidation processing time) orthe oxidizing power may be controlled to control a ratio of the Ccomponent, i.e., the carbon concentration, and one of the SiOCN layerand the SiOC layer may thus be formed while controlling the compositionratio. In addition, here, the process conditions, such as the pressurein the process chamber 201, the gas supply time, or the like, may becontrolled to finely adjust the ratio of the O component in the SiOCNlayer or the SiOC layer, i.e., the oxygen concentration, and thecomposition ratio of the SiOCN layer or the SiOC layer may thus be morefinely controlled.

In addition, here, it is preferable that the oxidation reaction of thefirst layer be unsaturated. For example, when the first layer having athickness of less than one atomic layer to several atomic layers isformed in steps 1 and 2, it is preferable that a portion of the firstlayer be oxidized. In this case, the oxidation is performed under theconditions in which the oxidation reaction of the first layer isunsaturated such that the entire first layer having a thickness of lessthan one atomic layer to several atomic layers is not oxidized.

The process conditions in step 3 may be the above-mentioned processconditions to cause the oxidation reaction of the first layer to beunsaturated, but are set to the following process conditions to causeeasy unsaturation of the oxidation reaction of the first layer:

Wafer temperature: 500 to 650° C.

Pressure in process chamber: 133 to 2,666 Pa

O₂ gas partial pressure: 33 to 2,515 Pa

O₂ gas supply flow rate: 1,000 to 5,000 sccm

N₂ gas supply flow rate: 300 to 3,000 sccm

O₂ gas supply time: 6 to 60 seconds

Remaining Gas Removal

After the second layer is formed, the valve 243 c of the third gassupply pipe 232 c is closed to stop supply of the O₂ gas. Here, theinside of the process chamber 201 is vacuum-exhausted by the vacuum pump246 in a state in which the APC valve 244 of the exhaust pipe 231 isopen (preferably, in a state in which the APC valve 244 is fully open)in order to remove either the O₂ gas or the reaction byproduct afternon-reaction or contribution to formation of the second layer andremaining in the process chamber 201 from the inside of the processchamber 201. In addition, here, supply of the N₂ gas into the processchamber 201 is maintained in a state in which the valves 243 g, 243 e,and 243 f are open. The N₂ gas serves as the purge gas to increase aneffect of removing the O₂ gas or the reaction byproduct afternon-reaction or contribution to formation of the second layer andremaining in the process chamber 201 from the inside of the processchamber 201.

In addition, here, the gas remaining in the process chamber 201 may notbe completely removed, and the inside of the process chamber 201 may notbe completely purged. When the gas remaining in the process chamber 201is minute, there is no bad influence in step 1 performed thereafter.Here, a flow rate of the N₂ gas supplied into the process chamber 201need not be a large flow rate, and for example, an amount of gassubstantially equal to a capacity of the reaction tube 203 (the processchamber 201) may be supplied to perform the purge such that there is nobad influence generated in step 1. As described above, as the inside ofthe process chamber 201 is not completely purged, the purge time can bereduced to improve throughput. In addition, consumption of the N₂ gasmay be suppressed to a necessary minimum value.

In addition to the O₂ gas, nitrous oxide (N₂O) gas, nitric oxide (NO)gas, nitrogen dioxide (NO₂) gas, ozone (O₃) gas, hydrogen (H₂)gas+oxygen (O₂) gas, H₂ gas+O₃ gas, vapor (H₂O) gas, carbon monoxide(CO) gas, carbon dioxide (CO₂) gas, or the like may be used as theoxygen-containing gas (oxidizing gas). In addition to the N₂ gas, a raregas, such as Ar gas, He gas, Ne gas, Xe gas, or the like, may be used asthe inert gas.

Perform Cycle Predetermined Number of Times

The above-mentioned steps 1 to 3 are set as one cycle, and the cycle maybe performed a predetermined number of times to form a film includingsilicon, oxygen, carbon and nitrogen, i.e., a silicon oxycarbonitride(SiOCN) film, or a film including silicon, oxygen and carbon, i.e., asilicon oxycarbide (SiOC) film, which has a predetermined compositionand a predetermined film thickness, on the wafer 200. The cycle ispreferably performed a plurality of times. That is, it is preferablethat a thickness of the SiOCN layer or the SiOC layer formed per cyclebe set to be smaller than a desired film thickness, and the cycle beperformed a plurality of times until the thickness arrives at thedesired film thickness.

When the cycle is performed a plurality of times, the phrase“predetermined gas is supplied to the wafer 200” in each step at leastafter a second cycle means “predetermined gas is supplied to a layerformed on the wafer 200, i.e., the outermost surface of the wafer 200,which is a stacked structure,” and the phrase “predetermined layer isformed on the wafer 200” means “predetermined layer is formed on a layerformed on the wafer 200, i.e., the outermost layer of the wafer 200,which is a stacked structure.” This is similar to the above-mentioneddescription. In addition, this will be similar in the following otherembodiments.

Purge and Atmospheric Pressure Recovery

When film-forming is performed to form a SiOCN film or a SiOC filmhaving a predetermined composition and a predetermined film thickness,the valves 243 e, 243 f, and 243 g are opened to supply N₂ gas servingas an inert gas into the process chamber 201 via the first inert gassupply pipe 232 e, the second inert gas supply pipe 232 f, and the thirdinert gas supply pipe 232 g and exhaust the N₂ gas via the exhaust pipe231. The N₂ gas may also serve as a purge gas, and allows the inside ofthe process chamber 201 to be purged with the inert gas, therebyremoving a gas or reaction byproducts remaining in the process chamber201 from the inside of the process chamber 201 (purging). Thereafter,the atmosphere in the process chamber 201 is substituted with the inertgas (inert gas substitution) to return the pressure in the processchamber 201 to a normal pressure (atmospheric pressure recovery).

Boat Unloading and Wafer Discharging

Then, the seal cap 219 is moved downward by the boat elevator 115 toopen the lower end of the reaction tube 203, and at the same time, theprocessed wafer 200 is unloaded from the lower end of the reaction tube203 to the outside of the reaction tube 203 (boat unloading) while beingsupported by the boat 217. Then, the processed wafer 200 is dischargedfrom the boat 217 (wafer discharging).

(3) Effects of the First Embodiment

According to the first embodiment, one or more of the following effectsare provided.

(a) According to the first embodiment, in step 2, when the TEA gas issupplied, first, the TEA gas is supplied at the first flow rate (firstTEA gas supply process). Then, after the pressure in the process chamber201 reaches a predetermined pressure, the TEA gas is supplied at thesecond flow rate that is less than the first flow rate while thepredetermined pressure is maintained in the process chamber 201 (secondTEA gas supply process). Thus, in step 2, a total supply rate of the TEAgas into the process chamber 201, i.e., the consumption rate of the TEAgas, may be less than when the TEA gas is continuously supplied at thefirst flow rate into the process chamber 201. As a result, costs forforming the SiOCN film or the SiOC film may be saved.

(b) According to the first embodiment, in step 2, the APC valve 244installed at the exhaust line configured to exhaust the inside of theprocess chamber 201 is set to have a first degree of opening when theTEA gas is supplied at the first flow rate, and is set to a seconddegree of opening that is greater than the first degree of opening whenthe TEA gas is supplied at the second flow rate that is greater than thefirst flow rate. That is, the exhaust conductance at the exhaust lineconfigured to exhaust the inside of the process chamber 201 is set to bea first exhaust conductance when the TEA gas is supplied at the firstflow rate, and is set to be a second exhaust conductance that is greaterthan the first exhaust conductance when the TEA gas is supplied at thesecond flow rate. In other words, when the TEA gas is supplied at thefirst flow rate, the degree of opening of the APC valve 244 ispreferably set to be the first degree of opening that is less (narrower)than the second degree of opening and the exhaust conductance ispreferably set to be the first exhaust conductance that is less than thesecond first exhaust conductance. In this case, when the TEA gas issupplied at the first flow rate, a total flow rate of gases suppliedinto the process chamber 201 (i.e., the sum of the flow rates of the TEAgas and the N₂ gas) is preferably greater than the exhaust flow rate ofa gas exhausted via the exhaust line. In this case, the pressure in theprocess chamber 201 may be rapidly raised to a predetermined pressurewithin a short time period. That is, a time needed to equalize thepressure in the process chamber 201 with the predetermined pressure maybe shortened. Since the pressure in the process chamber 201 can berapidly raised to a comparatively high pressure, the amount of carbon(C) present in the process chamber 201 may be increased, the amount ofcarbon (C) added to the first layer may be increased, and theconcentration of carbon (C) contained in the first layer may beincreased.

(c) According to the first embodiment, in step 2, the degree of opening(first degree of opening) of the APC valve 244 installed at the exhaustline configured to exhaust the inside of the process chamber 201 isfully closed to suspend control of the degree of opening of the APCvalve 244 when the TEA gas is supplied at the first flow rate, and iscontrolled by opening the APC valve 244 when the TEA gas is supplied atthe second flow rate. That is, the exhaust line configured to exhaustthe inside of the process chamber 201 is blocked when the TEA gas issupplied at the first flow rate, and is opened when the TEA gas issupplied at the second flow rate. Thus, the pressure in the processchamber 201 may be more rapidly raised. As a result, a rate andproductivity of forming the SiOCN film or the SiOC film may beincreased. In addition, since the pressure in the process chamber 201may be more rapidly raised to a comparatively high pressure, the amountof carbon present in the process chamber 201 may be increased, and theconcentration of carbon contained in the SiOCN film or the SiOC film maybe more increased.

(d) According to the first embodiment, in step 2, N₂ gas is supplied atthe third flow rate when the TEA gas is supplied at the first flow rate,and is supplied at the fourth flow rate that is less than the third flowrate when the TEA gas is supplied at the second flow rate. That is, whenthe flow rate of the TEA gas supplied into the process chamber 201 isreduced, the flow rate of N₂ gas supplied into the process chamber 201is also reduced. Thus, after the flow rate of the TEA gas supplied intothe process chamber 201 is reduced, the partial pressure of the TEA gasin the process chamber 201, i.e., the concentration of the TEA gas inthe process chamber 201, may be suppressed from being lowered. Inaddition, an actual supply rate of the TEA gas to the wafer 200, i.e.,the number of TEA molecules supplied to the wafer 200, may be suppressedfrom being reduced. As a result, the amount of carbon (C) added to theSiOCN film or the SiOC film, i.e., the concentration of carbon (C)contained in the SiOCN film or the SiOC film, may be suppressed frombeing reduced.

(e) According to the first embodiment, in step 2, the ratio of the flowrate of the TEA gas to that of the N₂ gas supplied into the processchamber 201 is maintained constant. That is, when the flow rates of theTEA gas and the N₂ gas supplied into the process chamber 201 are loweredto the second flow rate and the fourth flow rate, respectively, thesecond flow rate and the fourth flow rate are set to satisfy (first flowrate:third flow rate=second flow rate:fourth flow rate). Accordingly, atleast after the pressure in the process chamber 201 reaches thepredetermined pressure, the partial pressure of the TEA gas in theprocess chamber 201 is maintained constant. As a result, an actualsupply rate of the TEA gas to the wafer 200 may be maintained constantboth before and after the flow rate of the TEA gas is reduced. In otherwords, the number of TEA molecules supplied to the wafer 200 may bemaintained constant both before and after the flow rate of the TEA gasis reduced. As a result, the amount of carbon (C) added to the SiOCNfilm or the SiOC film, i.e., the concentration of carbon (C) containedin the SiOCN film or the SiOC film, may be suppressed from beinglowered.

(f) According to the first embodiment, in step 2, when the flow rate ofthe TEA gas supplied into the process chamber 201 is lowered, the amountof carbon (C) added to the SiOCN film or the SiOC film may be changed bychanging the ratio of the flow rate of the TEA gas to that of the N₂ gassupplied into the process chamber 201, i.e., by changing the partialpressure of the TEA gas in the process chamber 201. For example, whenthe flow rate of the TEA gas supplied into the process chamber 201 islowered, the partial pressure of the TEA gas in the process chamber 201may be lowered by adjusting the flow rate of the N₂ gas to satisfy((fourth flow rate)>(third flow rate)×(second flow rate)/(first flowrate)), i.e., lowering the rate of the TEA gas, thereby reducing theamount of carbon (C) added to the SiOCN film or the SiOC film. Inaddition, for example, when the flow rate of the TEA gas supplied intothe process chamber 201 is reduced, the partial pressure of the TEA gasin the process chamber 201 may be raised by adjusting the flow rate ofthe N₂ gas to satisfy (fourth flow rate)<(third flow rate)×(second flowrate)/(first flow rate), i.e., by increasing the rate of the TEA gas,thereby increasing the amount of carbon (C) added to the first layer.

(g) According to the first embodiment, a first layer containing Si, N,and C is formed by alternately performing steps 1 and 2, step 3 may beperformed to oxidize the first layer to be modified into a SiOCN layeror a SiOC layer as a second layer by supplying O₂ gas (which is anoxygen-containing gas) as a second reactive gas, thereby adjusting acomposition ratio among oxygen, carbon, and nitrogen contained in aSiOCN film or a SiOC film. In addition, in this case, O₂ gas may bethermally activated and supplied to increase Si—O bonds and reduce Si—Cbonds, Si—N bonds, and Si—Si bonds in the SiOCN film or the SiOC film,due to an operation of the thermal oxidization. That is, thiscomposition ratio may be changed in a direction of increasing oxygenconcentration and a direction of reducing nitrogen concentration, carbonconcentration, and silicon concentration. In addition, in this case, thethermal oxidation time or an oxidizing power of the thermal oxidationmay be increased to change this composition ratio in a direction ofincreasing oxygen concentration more or a direction of reducing nitrogenconcentration, carbon concentration, and silicon concentration more. Inaddition, in this case, a ratio of the oxygen component in the SiOCNfilm or the SiOC film, i.e., the concentration of oxygen, may be finelycontrolled by controlling the pressure in the process chamber 201 orprocess conditions, e.g., a gas supply time, thereby more finelycontrolling the composition ratio of the SiOCN film or the SiOC film.Accordingly, the dielectric constant, etching resistance, or insulatingproperties of the SiOCN film or the SiOC film may be improved.

Second Embodiment of the Present Invention

Next, a second embodiment of the present invention will be described.

The first embodiment has been described above with respect to a processof forming a silicon oxycarbonitride film or a silicon oxycarbide filmhaving a predetermined composition and a predetermined film thickness onthe wafer 200 using an oxygen-containing gas (O₂ gas) as a secondreactive gas. In contrast, the second embodiment will be described belowwith respect to a process of forming a silicon carbonitride (SiCN) filmhaving a predetermined composition and a predetermined film thickness onthe wafer 200 using a nitrogen-containing gas (NH₃ gas) as a secondreactive gas.

Specifically, in the second embodiment, an example of a process offorming a silicon carbonitride (SiCN) film having a predeterminedcomposition and a predetermined film thickness on the wafer 200 in theprocess chamber 201 by performing a cycle a predetermined number oftimes (n times), the cycle including: a process of forming asilicon-containing layer containing chlorine on the wafer 200 in theprocess chamber 201 by supplying a chlorosilane-based source gas (HCDSgas) to the wafer 200; a process of forming a first layer containingsilicon, nitrogen, and carbon by modifying the silicon-containing layercontaining chlorine by supplying an amine-based gas (TEA gas) as a firstreactive gas to the wafer 200 in the process chamber 201; and a processof forming a SiCN film as a second layer by modifying the first layer bysupplying a nitrogen-containing gas (NH₃ gas) as a second reactive gasto the wafer 200 will be described.

FIG. 6 is a view showing a film-forming flow according to a secondembodiment of the present invention. FIG. 7 is a view showing gas supplytiming in a film-forming sequence according to the second embodiment ofthe present invention. The second embodiment is substantially the sameas the first embodiment, except that in step 3, thermally activated NH₃gas is used as a second reactive gas. Step 3 according to the secondembodiment will now be described.

Step 3

NH₃ Gas Supply

After step 2 is terminated and a remaining gas in the process chamber201 is removed, the valve 243 d of the fourth gas supply pipe 232 d isopened to cause NH₃ gas to flow into the fourth gas supply pipe 232 d.The flow rate of the NH₃ gas flowing through the fourth gas supply pipe232 d is adjusted by the mass flow controller 241 d. Theflow-rate-adjusted NH₃ gas is supplied into the process chamber 201 viathe gas supply hole 250 c of the third nozzle 249 c. The NH₃ gassupplied into the fourth process chamber 201 is thermally activated(excited), and is exhausted via the exhaust pipe 231. In this case, thethermally activated NH₃ gas is supplied to the wafer 200.Simultaneously, the valve 243 g is opened to cause N₂ gas to flow intothe third inert gas supply pipe 232 g. The N₂ gas is supplied into theprocess chamber 201 together with the NH₃ gas, and is exhausted via theexhaust pipe 231. In this case, in order to prevent invasion of the NH₃gas into the first nozzle 249 a and second nozzle 249 b, the valves 243e and 243 f are opened to cause the N₂ gas to flow into the first inertgas supply pipe 232 e and the second inert gas supply pipe 232 f. The N₂gas is supplied into the process chamber 201 via the first gas supplypipe 232 a, the second gas supply pipe 232 b, the first nozzle 249 a,and the second nozzle 249 b, and is exhausted via the exhaust pipe 231.

In this case, the APC valve 244 may be appropriately adjusted toregulate the pressure in the process chamber 201 to be within, forexample, a range of 1 to 3,000 Pa. By regulating the pressure in theprocess chamber 201 to a comparatively high pressure as described above,the NH₃ gas may be thermally activated in a non plasma state. Inaddition, when the NH₃ gas is thermally activated and supplied, a softreaction may thus occur, thereby softly performing nitridation whichwill be described below. The supply flow rate of the NH₃ gas controlledby the mass flow controller 241 c may be a flow rate that falls within,for example, a range of 100 to 10,000 sccm. The supply flow rate of theN₂ gas controlled by each of the mass flow controllers 241 g, 241 e, and241 f may be a flow rate that falls within, for example, a range of 100to 10,000 sccm. In this case, the partial pressure of the NH₃ gas in theprocess chamber 201 falls within a range of 0.01 to 2,970 Pa. A time inwhich the thermally activated NH₃ gas is supplied to the wafer 200,i.e., a gas supply time (exposure time), is within, for example, a rangeof 1 to 120 seconds, and preferably 1 to 60 seconds. In this case, atemperature of the heater 207 is set such that the temperature of thewafer 200 is within a range of, for example, 250 to 700° C., preferably300 to 650° C., and more preferably 350 to 600° C., as in steps 1 and 2.

In this case, the gas flowing into the process chamber 201 is the NH₃gas that is thermally activated by increasing the temperature in theprocess chamber 201, and neither HCDS gas nor TEA gas flows into theprocess chamber 201. Accordingly, the NH₃ gas does not cause a gaseousreaction, and the activated NH₃ gas reacts with at least a portion ofthe first layer including Si, N, and C formed on the wafer 200 in step2. Accordingly, the first layer is nitrided to be modified as a layerincluding silicon, carbon and nitrogen, which is a second layer, i.e., asilicon carbonitride (SiCN) layer.

In addition, by thermally activating NH₃ gas and flowing it into theprocess chamber 201, the first layer may be thermally nitrided to bemodified (changed) into a SiCN layer. In this case, the first layer ismodified into the SiCN layer while increasing an N component in thefirst layer. In addition, in this case, through an operation of thethermal nitridation due to the NH₃ gas, Si—N bonds increase and Si—Cbonds and Si—Si bonds decrease in the first layer, thereby lowering theratio of a C component and a ratio of a Si component in the first layer.That is, the first layer may be modified into the SiCN layer whilechanging the composition ratio in a direction of increasing nitrogenconcentration and a direction of reducing carbon concentration andsilicon concentration. In addition, in this case, process conditions,such as the pressure in the process chamber 201 or the gas supply time,may be controlled to finely adjust a ratio of an N component (i.e., theconcentration of nitrogen) in the SiCN layer, thereby more finelycontrolling the composition ratio of the SiCN layer.

In this case, the nitridation reaction of the first layer is preferablyunsaturated. For example, when the first layer is formed to a thicknessof less than one atomic layer to several atomic layers in steps 1 and 2,a portion of the first layer is preferably nitrided. In this case, thenitridation is performed under conditions in which the nitridationreaction of the first layer is unsaturated such that the entire firstlayer having a thickness of less than one atomic layer to several atomiclayers is not nitrided.

Further, while the process conditions in step 3 may be theabove-mentioned process conditions to cause the nitridation reaction ofthe first layer to be unsaturated, the process conditions in step 3 areset to the following process conditions to easily cause unsaturation ofthe nitridation reaction of the first layer:

Wafer temperature: 500 to 650° C.

Pressure in process chamber: 133 to 2,666 Pa

NH₃ gas partial pressure: 33 to 2,515 Pa

NH₃ gas supply flow rate: 1,000 to 5,000 sccm

N₂ gas supply flow rate: 300 to 3,000 sccm

NH₃ gas supply time: 6 to 60 seconds

Remaining Gas Removal

After the second layer is formed, the valve 243 d of the fourth gassupply pipe 232 d is closed to suspend the supply of the NH₃ gas. Inthis case, the inside of the process chamber 201 is vacuum-exhausted bythe vacuum pump 246 in a state in which the APC valve 244 of the exhaustpipe 231 is open (preferably, in a state in which the APC valve 244 isfully opened) in order to remove the NH₃ gas or reaction byproductsafter non-reaction or contribution to formation of the second layer andremaining in the process chamber 201 from the inside of the processchamber 201. In addition, here, supply of the N₂ gas into the processchamber 201 is maintained in a state in which the valves 243 g, 243 eand 243 f are open. The N₂ gas serves as the purge gas, and thus aneffect of removing the O₂ gas or the reaction byproduct afternon-reaction or contribution to formation of the second layer andremaining in the process chamber 201 from the inside of the processchamber 201 can be increased. In addition, in this case, the supply ofthe N₂ gas into the process chamber 201 is maintained while the valves243 g, 243 e, and 243 f are open. The N₂ gas serves as a purge gas toincrease an effect of removing the NH₃ gas or the reaction byproductsafter non-reaction or contribution to formation of the second layer andremaining in the process chamber 201 from the inside of the processchamber 201.

In addition, here, the gas remaining in the process chamber 201 may notbe completely removed, and the inside of the process chamber 201 may notbe completely purged. When the gas remaining in the process chamber 201is minute, there is no bad influence in step 1 performed thereafter. Inthis case, the flow rate of the N₂ gas supplied into the process chamber201 need not be a large flow rate, and for example, an amount of gassubstantially equal to a capacity of the reaction tube 203 (the processchamber 201) may be supplied to perform the purge such that there is nobad influence generated in step 1. As described above, as the inside ofthe process chamber 201 is not completely purged, the purge time can bereduced to improve throughput. In addition, consumption of the N₂ gascan be suppressed to a necessary minimum value.

In addition to the NH₃ gas, a gas including a compound such as diazene(N₂H₂) gas, hydrazine (N₂H₄) gas, N₃H₈ gas, or the like, may be used asa nitrogen-containing gas (nitriding gas). In addition to the N₂ gas, arare gas such as Ar gas, He gas, Ne gas, Xe gas, or the like, may beused as the inert gas.

Perform Cycle Predetermined Number of Times

The above-mentioned steps 1 to 3 are set as one cycle, and the cycle maybe performed at least once (a predetermined number of times) to form afilm including silicon, carbon and nitrogen, i.e., a siliconcarbonitride (SiCN) film, which has a predetermined composition and apredetermined film thickness, on the wafer 200. The cycle is preferablyperformed a plurality of times. That is, it is preferable that athickness of a SiCN layer formed per cycle be set to be smaller than adesired film thickness, and the cycle be performed a plurality of timesuntil the thickness arrives at the desired film thickness.

According to the second embodiment, effects similar to those of thefirst embodiment may be achieved.

Specifically, in step 2, during supply of TEA gas, the TEA gas is firstsupplied at a first flow rate and is then supplied at a second flow ratethat is less than the first flow rate while maintaining the pressure inthe process chamber 201 at a predetermined pressure after the pressurein the process chamber 201 reaches the pressure process chamber 201.Accordingly, consumption of the TEA gas may be lowered, thereby savingcosts for forming the SiCN film.

In addition, in step 2, the degree of opening of the APC valve 244installed at the exhaust line configured to exhaust the inside of theprocess chamber 201 is set to be a first degree of opening when the TEAgas is supplied at the first flow rate, and is set to be a second degreeof opening that is greater than the first degree of opening when the TEAgas is supplied at the second flow rate that is greater than the firstflow rate. Thus, the pressure in the process chamber 201 may be rapidlyraised to the predetermined pressure within a short time period, and theamount of carbon (C) present in the process chamber 201 may increase,thereby increasing the concentration of carbon (C) contained in thefirst layer.

In addition, in step 2, the degree of opening (first degree of opening)of the APC valve 244 installed at the exhaust line configured to exhaustthe inside of the process chamber 201 is fully closed to suspend controlof the degree of opening of the APC valve 244 (to block the exhaustline) when the TEA gas is supplied at the first flow rate, and the APCvalve 244 is opened to perform control of the degree of opening of theAPC valve 244 (to open the exhaust line) when the TEA gas is supplied atthe second flow rate. Thus, the pressure in the process chamber 201 maybe rapidly raised, thereby improving the productivity of forming theSiCN film. In addition, the concentration of carbon (C) contained in theSiCN film may be increased.

In addition, in step 2, the N₂ gas is supplied at a third flow rate whenthe TEA gas is supplied at the first flow rate, and is supplied at afourth flow rate that is less than the third flow rate when the TEA gasis supplied at the second flow rate, thereby preventing a decrease inthe partial pressure of the TEA gas in the process chamber 201 andsuppressing the concentration of carbon (C) contained in the SiCN filmfrom being lowered.

In addition, in step 2, a ratio of the flow rate of the TEA gas to thatof the N₂ gas supplied into the process chamber 201 is maintainedconstant to maintain the partial pressure of the TEA gas in the processchamber 201 constant, thereby suppressing the concentration of carbon(C) contained in the SiCN film from being lowered.

In addition, in step 2, when the flow rate of the TEA gas supplied intothe process chamber 201 is lowered, the concentration of carbon (C)added to the SiCN film may be changed by changing the ratio of the flowrate of the TEA gas to that of the N₂ gas supplied into the processchamber 201.

In addition, according to the second embodiment, after the first layercontaining Si, N, and C is formed by alternately performing steps 1 and2, step 3 is performed to supply NH₃ gas (which is a nitrogen-containinggas) as a second reactive gas to nitrate the first layer to be modifiedinto a SiCN layer as a second layer, thereby adjusting a compositionratio of carbon to nitrogen contained in the SiCN film. In addition, inthis case, the NH₃ gas may be thermally activated and supplied toincrease Si—N bonds and reduce Si—C bonds and Si—Si bonds in the SiOCNfilm or the SiOC film, due to an operation of the thermal nitridation.That is, the composition ratio may be changed in a direction ofincreasing nitrogen concentration and a direction of reducing carbonconcentration and silicon concentration. In addition, in this case, aratio of a nitrogen component (i.e., the concentration of nitrogen) inthe SiCN film may be finely controlled by controlling the pressure inthe process chamber 201 or process conditions, e.g., a gas supply time,thereby more finely controlling the composition ratio of the SiCN film.Accordingly, the dielectric constant, etching resistance, or insulatingproperties of the SiCN film or the SiOC film may be improved.

Other Embodiments of the Present Invention

While the present invention has been particularly described withreference to exemplary embodiments thereof, the present invention is notlimited thereto and various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

For example, although in the previous embodiments, a process of changingthe flow rate of TEA gas in two steps so as to form a thin film on thewafer 200 has been described above, the present invention is not limitedthereto. That is, the flow rate of the TEA gas may be changed in threesteps or four steps, i.e., multi-steps, to form a thin film on the wafer200. In this case, after the pressure in the process chamber 201 becomesa predetermined pressure, the degree of opening of the APC valve 244 mayalso be controlled to maintain the pressure in the process chamber 201at the predetermined pressure, and the flow rate of N₂ gas may also becontrolled to maintain the partial pressure of the TEA gas in theprocess chamber 201 at a constant level, thereby obtaining the effectsof the previous embodiments.

In addition, although, according to the previous embodiments, forexample, the flow rate of the TEA gas is changed in two steps so as toform a thin film on the wafer 200, the present invention is not limitedthereto. That is, a thin film may be formed on the wafer 200 by changingthe flow rate of a source gas, e.g., HCDS gas, in two steps, changingthe flow rate of an oxygen-containing gas, e.g., O₂ gas, in two steps,or changing the flow rate of a nitrogen-containing gas, e.g., NH₃ gas,in two steps. That is, during not only a process of supplying the firstreactive gas (amine-based gas) but also a process of supplying a sourcegas or a process of supplying a second reactive gas (oxygen-containinggas or nitrogen-containing gas), a first supply process of supplying thesource gas or the second reactive gas, which is to be used during apresent process, at the first flow rate in a state in which exhaustingof the inside of the process chamber 201 is suspended, until thepressure in the process chamber 201 becomes the same as a predeterminedpressure; and a second supply process of supplying the source gas or thesecond reactive gas, which is to be used during a present process, atthe second flow rate (which is less than the first flow rate) whilemaintaining the pressure in the process chamber 201 at the predeterminedpressure after the pressure in the process chamber 201 reaches thepredetermined pressure, in a state in which the inside of the processchamber 201 is exhausted may be performed. FIG. 9 illustrates an exampleof a process of forming a SiOCN film or a SiOC film on the wafer 200while changing the flow rates of a source gas (HCDS gas), a firstreactive gas (TEA gas), and an oxygen-containing gas (O₂ gas) in twosteps. However, since a carbon-containing gas which is a carbon source,such as TEA gas, is comparatively expensive compared to anoxygen-containing gas or a nitrogen-containing gas and the concentrationof carbon (C) in a thin film is comparatively difficult to increase, itis possible to achieve remarkable effects of the present invention whena thin film is formed on the wafer 200 while changing the flow rate ofthe carbon-containing gas which is a carbon source in two steps.

In addition, although in the previous embodiments, for example, when thefirst layer containing Si, N, and C is formed, the chlorosilane-basedsource gas and the amine-based gas are sequentially supplied to thewafer 200 in the process chamber 201, the order of supplying these gasesmay be reversed. That is, the amine-based gas may be supplied and thenthe chlorosilane-based source gas may be supplied. In other words, oneof the chlorosilane-based source gas and the amine-based gas may besupplied and the other may then be supplied. By reversing the order ofsupplying these gases as described above, a film quality or compositionratio of a thin film to be formed may be changed.

In addition, although in the previous embodiments, for example, duringthe process of forming the first layer, the first layer containing Si,N, and C is formed by alternately performing steps 1 and 2, the firstlayer containing Si, N, and C may be formed by alternately performingsteps 1 and 2 a predetermined number of times. That is, during theprocess of forming the first layer, the first layer containing Si, N,and C may be formed by alternately performing steps 1 and 2 apredetermined number of times (at least once). Specifically, in thefirst embodiment, a SiOCN film or a SiOC film may be formed on the wafer200 by performing a cycle a predetermined number of times, the cycleincluding a process of forming the first layer containing Si, N, and Cby alternately performing steps 1 and 2 a predetermined number of times(at least once), and a process of oxidizing the first layer to form aSiOCN layer or a SiOC layer as a second layer by supplying anoxygen-containing gas as a second reactive gas. In the secondembodiment, a SiCN film may be formed on the wafer 200 by performing acycle a predetermined number of times, the cycle including a process offorming the first layer containing Si, N, and C by alternatelyperforming steps 1 and 2 a predetermined number of times (at leastonce), and a process of nitrating the first layer to form a SiCN layeras a second layer by supplying a nitrogen-containing gas as a secondreactive gas.

In addition, although in the previous embodiments, for example, in step1, when a seed layer containing a specific element (silicon) and ahalogen element (chlorine) is formed using a chlorosilane-based sourcegas is used as a source gas, a silane-based source gas havinghalogen-based ligands other than chloro groups may be used instead ofthe chlorosilane-based source gas. For example, a fluorosilane-basedsource gas may be used instead of the chlorosilane-based source gas.Here, the fluorosilane-based source gas refers to a fluorosilane-basedsource material in a gaseous state, for example, a gas obtained byevaporating a fluorosilane-based source material in a liquid state undera normal temperature and a normal pressure, or a fluorosilane-basedsource material in a gaseous state under a normal temperature and anormal pressure. In addition, the fluorosilane-based source materialrefers to a silane-based source material including a fluoro groupserving as a halogen group, i.e., a source material including at leastsilicon (Si) and fluorine (F). That is, here, the fluorosilane-basedsource material may be referred to as a halide. For example, a siliconfluoride gas such as tetrafluorosilane, i.e., silicontetrafluoride(SiF₄) gas, hexafluorodisilane (Si₂F₆) gas, or the like, may be used asthe fluorosilane-based source gas. In this case, when the seed layerincluding a prescribed element and a halogen element is formed, thefluorosilane-based source gas is supplied to the wafer 200 in theprocessing container. In this case, the seed layer is a layer includingSi and F, i.e., a silicon-containing layer including F.

In addition, for example, in the previous embodiments, while the examplein which the amine-based gas is used as the first reactive gas when thesilicon-containing layer including Cl serving as the seed layer ischanged (modified) into the first layer including Si, N and C has beendescribed, for example, a gas including an organic hydrazine compound,i.e., an organic hydrazine-based gas, may be used as the first reactivegas, instead of the amine-based gas. In addition, the gas including theorganic hydrazine compound may be simply referred to as an organichydrazine compound gas or an organic hydrazine gas. Here, the organichydrazine-based gas refers to an organic hydrazine in a gaseous state,for example, a gas obtained by evaporating an organic hydrazine in aliquid state under a normal temperature and a normal pressure, or a gasincluding a hydrazine group such as organic hydrazine in a gaseous stateunder a normal temperature and a normal pressure. The organichydrazine-based gas is a gas composed of three elements of carbon (C),nitrogen (N) and hydrogen (H) and containing no silicon, or a gascontaining no silicon and no metal. For example, a methylhydrazine-basedgas obtained by evaporating monomethylhydrazine [(CH₃)HN₂H₂, abbreviatedto MMH], dimethylhydrazine [(CH₃)₂N₂H₂, abbreviated to DMH],trimethylhydrazine [(CH₃)₂N₂(CH₃)H, abbreviated to TMH], or the like, oran ethylhydrazine-based gas obtained by evaporating ethylhydrazine[(C₂H5)HN₂H₂, abbreviated to EH] or the like may be used as the organichydrazine-based gas. In this case, the organic hydrazine-based gas issupplied to the wafer 200 in the processing container when thesilicon-containing layer including Cl is changed (modified) into thefirst layer including Si, N and C.

In addition, in the previous embodiments, while the example in which theSiOCN film or the SiOC film is formed on the wafer 200 using a sourcegas, an amine-based gas, or an oxygen-containing gas or the example inwhich the SiCN film is formed on the wafer 200 using a source gas, anamine-based gas, or a nitrogen-containing gas has been described, thepresent invention is not limited thereto.

For example, even when a SiOCN film or a SiOC film is formed on thewafer 200 using a source gas, an amine-based gas, a carbon-containinggas, and an oxygen-containing gas, or when a SiCN film is formed on thewafer 200 using a source gas, an amine-based gas, a carbon-containinggas, and a nitrogen-containing gas, the present invention may be appliedthereto. That is, the present invention may be applied to a case inwhich a cycle including a source gas supply process, an amine-based gassupply process, a carbon-containing gas supply process, and anoxygen-containing gas supply process is performed a predetermined numberof times to form a SiOCN film or a SiOC film on the wafer 200, or a casein which a cycle including a source gas supply process, an amine-basedgas supply process, a carbon-containing gas supply process, and anitrogen-containing gas supply process is performed a predeterminednumber of times to form a SiCN film on the wafer 200.

In addition, for example, the present invention may be applied to a casein which a SiCN film is formed on the wafer 200 using a source gas andan amine-based gas or a case in which a SiCN film is formed on the wafer200 using a source gas, an amine-based gas, and a carbon-containing gas.That is, the present invention may also be applied to a case in which acycle including a source gas supply process and an amine-based gassupply process is performed a predetermined number of times to form aSiCN film on the wafer 200 or a case in which a cycle including a sourcegas supply process, an amine-based gas supply process, and acarbon-containing gas supply process is performed a predetermined numberof times to form a SiCN film on the wafer 200.

In addition, the present invention may be applied to a case in which asilicon boron carbonitride (SiBCN) film is formed on the wafer 200 usinga source gas, an amine-based gas, and a boron-containing gas, a case inwhich a SiBCN is formed on the wafer 200 using a source gas, anamine-based gas, a boron-containing gas, a carbon-containing gas, and anitrogen-containing gas, or a case in which a silicon boronitride (SiBN)film is formed on the wafer 200 using a source gas, an amine-based gas,a boron-containing gas, and a nitrogen-containing gas. That is, thepresent invention may also be applied to a case in which a cycleincluding a source gas supply process, an amine-based gas supplyprocess, and a boron-containing gas supply process is performed apredetermined number of times to form a SiBCN film on the wafer 200, acase in which a cycle including a source gas supply process, anamine-based gas supply process, a boron-containing gas supply process, acarbon-containing gas supply process, and a nitrogen-containing gassupply process is performed a predetermined number of times to form aSiBCN film on the wafer 200, or a case in which a cycle including asource gas supply process, an amine-based gas supply process, aboron-containing gas supply process, and a nitrogen-containing gassupply process is performed a predetermined number of times to form aSiBN film on the wafer 200.

In addition, the present invention may be applied to a case in which aboron carbonitride (BCN) film is formed on the wafer 200 using aboron-containing gas and an amine-based gas, a case in which a BCN filmis formed on the wafer 200 using a boron-containing gas, an amine-basedgas, a carbon-containing gas, and a nitrogen-containing gas, or a casein which a boron nitride (BN) film is formed on the wafer 200 using aboron-containing gas, an amine-based gas, and a nitrogen-containing gas.That is, the present invention may also be applied to a case in which acycle including a boron-containing gas supply process and an amine-basedgas supply process is performed a predetermined number of times to forma BCN film on the wafer 200, a case in which a cycle including aboron-containing gas supply process, an amine-based gas supply process,a carbon-containing gas supply process, and a nitrogen-containing gassupply process is performed a predetermined number of times to form aBCN film on the wafer 200, or a case in which a cycle including aboron-containing gas supply process, an amine-based gas supply process,and a nitrogen-containing gas supply process is performed apredetermined number of times to form a BN film on the wafer 200.

In this case, for example, a hydrocarbon-based gas, such as acetylene(C₂H₂) gas, propylene (C₃H₆) gas, or ethylene (C₂H₄) gas, may be used asthe carbon-containing gas. In addition, for example, an inorganic gassuch as boron trichloride (BCl₃) gas or diborane (B₂H₆) gas, or anorganic gas such as a borazine-based gas (hereinafter referred to as anorganic borazine compound) may be used as the boron-containing gas. Asthe source gas, the amine-based gas, the oxygen-containing gas, and thenitrogen-containing gas may be the same as those in the previousembodiments. In addition, in this case, process conditions may be thesame as those in the previous embodiments.

Furthermore, in this case, during the amine-based gas supply process,the flow rate of the amine-based gas may be changed in two steps asdescribed above. The flow rates of other gases (the source gas, theboron-containing gas, the carbon-containing gas, the oxygen-containinggas, and nitrogen-containing gas) may be changed in two steps asdescribed above. However, since the amine-based gas or thecarbon-containing gas which is a carbon source, e.g., C₃H₆ gas, iscomparatively expensive compared to the oxygen-containing gas or thenitrogen-containing gas and the concentration of carbon (C) in a thinfilm is comparatively difficult to increase, it is possible to achieveremarkable effects of the present invention when a thin film is formedon the wafer 200 while changing the flow rate of the amine-based gas orthe flow rate of the carbon-containing gas in two steps. In addition,since the organic borazine compound gas is comparatively expensive, itis also possible to achieve remarkable effects of the present inventionwhen a thin film is formed on the wafer 200 while changing the flow rateof the organic borazine compound gas used as the boron-containing gas.

As described above, the present invention may be preferably applied toan entire substrate processing process using a source gas and anamine-based gas.

In addition, the present invention may be applied to, for example, acase in which a SiCN film is formed on the wafer 200 using a source gasand an aminosilane-based source gas, or a case in which a SiBCN film ora SiBN film having a borazine annular skeleton is formed on the wafer200 using a source gas and an organic borazine compound gas. That is,the present invention may be applied to a case in which a SiCN film isformed on the wafer 200 by performing a cycle including a source gassupply process and an aminosilane-based source gas supply process apredetermined number of times, or a case in which a SiBCN film or a SiBNfilm having a borazine annular skeleton is formed on the wafer 200 byperforming a cycle including a source gas supply process and an organicborazine compound gas supply process a predetermined number of times.

In this case, for example, trisdimethylaminosilane (Si[N(CH₃)₂]₃H,abbreviated to 3DMAS) or the like may be used as the aminosilane-basedsource gas. Further, for example, n,n′,n″-trimethylborazine (abbreviatedto TMB) or the like may be used as the organic borazine compound gas.The source gas in the previous embodiments may be used as the sourcegas. In this case, process conditions may be, similar to, for example,those of the above-mentioned embodiment.

In addition, in this case, during the aminosilane-based source gassupply process, the flow rate of the aminosilane-based source gas may bechanged in two steps as described above. During the organic borazinecompound gas supply process, the flow rate of the organic borazinecompound gas may be changed in two steps as described above. During thesource gas supply process, the flow rate of the source gas may bechanged in two steps as described above. However, since theaminosilane-based source gas or the organic borazine compound gas iscomparatively expensive, it is possible to achieve remarkable effects ofthe present invention when a thin film is formed on the wafer 200 whilechanging the flow rates of these gases in two steps.

As described above, the present invention may be applied to a substrateprocessing process using the source gas and the aminosilane-based gas ora substrate processing process using the source gas and the organicborazine compound gas.

In addition, in the previous embodiments, the example in which anamine-based gas which is a gas containing carbon and nitrogen (carbon-and nitrogen-containing gas) is used as a reactive gas has beendescribed above, but the present invention is not limited thereto. Forexample, the present invention may also be applied to a case in whichtwo types of gases, e.g., a carbon-containing gas and anitrogen-containing gas, are used as a reactive gas, instead of theamine-based gas.

For example, the present invention may also be applied to a case inwhich a cycle including a source gas supply process, a carbon-containinggas supply process, a nitrogen-containing gas supply process, and anoxygen-containing gas supply process is performed a predetermined numberof times to form a SiOCN film on the wafer 200, or a case in which acycle including a source gas supply process, a carbon-containing gassupply process, and a nitrogen-containing gas supply process isperformed a predetermined number of times to form a SiCN film on thewafer 200. In this case, a hydrocarbon-based gas, such as propylene(C₃H₆) gas, acetylene (C₂H₂) gas, or ethylene (C₂H₄) gas, may be used asthe carbon-containing gas, and the nitrogen-containing gas according tothe second embodiment described above may be used as thenitrogen-containing gas.

Furthermore, the present invention may also be applied to a case inwhich a cycle including a source gas supply process, a carbon-containinggas supply process, a boron-containing gas supply process, and anitrogen-containing gas supply process is performed a predeterminednumber of times to form a SiBCN film on the wafer 200. In this case, thecarbon-containing gas, the boron-containing gas, and thenitrogen-containing gas are as described above.

In addition, the present invention may also be applied to a case inwhich a cycle including a boron-containing gas supply process, acarbon-containing gas supply process, and a nitrogen-containing gassupply process is performed a predetermined number of times to form aBCN film on the wafer 200, or a case in which a cycle including aboron-containing gas supply process and a nitrogen-containing gas supplyprocess is performed a predetermined number of times to form a BN filmon the wafer 200. In this case, the boron-containing gas, thecarbon-containing gas, and the nitrogen-containing gas are as describedabove.

In this case, during the carbon-containing gas supply process, the flowrate of the carbon-containing gas may be changed in two steps asdescribed above, and the flow rates of other gases (the source gas, theoxygen-containing gas, the nitrogen-containing gas, and boron-containinggas) may be changed in two steps as described above. However, since acarbon-containing gas which is a carbon source, such as C₃H₆ gas, iscomparatively expensive compared to an oxygen-containing gas or anitrogen-containing gas and the concentration of carbon (C) in a thinfilm is comparatively difficult to increase, it is possible to achieveremarkable effects of the present invention when a thin film is formedon the wafer 200 while changing the flow rate of the carbon-containinggas which is a carbon source in two steps.

As described above, the present invention may be preferably applied to acase in which a thin film is formed using a reactive gas, such as asource gas and carbon-containing gas.

When a silicon-based insulating film or a boron-based insulating filmformed by the methods according to the previous embodiments and modifiedexamples thereof is used as a sidewall spacer, a device-formingtechnique having a small leak current and good machinability can beprovided.

When a silicon-based insulating film or a boron-based insulating filmformed by the methods according to the previous embodiments and modifiedexamples thereof is used as an etching stopper, a device-formingtechnique having good machinability can be provided.

According to the previous embodiments or modified examples thereof, asilicon-based insulating film or a boron-based insulating film having anideal stoichiometric ratio can be formed without using plasma even in alow temperature region. In addition, since the silicon-based insulatingfilm or the boron-based insulating film can be formed without usingplasma, it may be applied to a process in which plasma damage may occur,for example, a process of forming an SADP film of DPT.

In addition, although in the previous embodiments, the example in whichthe silicon-based insulating layer (the SiOCN film, the SiOC film, andthe SiCN film) including silicon (which is a semiconductor element)serving as an oxycarbonitride film, an oxycarbide film, or acarbonitride film has been described, the present invention may beapplied to a case in which a metal-based thin film including a metalelement, such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum(Ta), aluminum (Al), molybdenum (Mo), etc., is formed.

That is, the present invention may be preferably applied to a case inwhich a metal oxycarbonitride film, such as a titanium oxycarbonitride(TiOCN) film, a zirconium oxycarbonitride (ZrOCN) film, a hafniumoxycarbonitride (HfOCN) film, a tantalum oxycarbonitride (TaOCN) film,an aluminum oxycarbonitride (AlOCN) film, a molybdenum oxycarbonitride(MoOCN) film, etc. is formed.

In addition, for example, the present invention may be applied to a casein which a metal oxycarbide film, such as a titanium oxycarbide (TiOC)film, a zirconium oxycarbide (ZrOC) film, a hafnium oxycarbide (HfOC)film, a tantalum oxycarbide (TaOC) film, an aluminum oxycarbide (AlOC)film, a molybdenum oxycarbide (MoOC) film, etc. is formed.

Further, for example, the present invention may be applied to a case inwhich a metal carbonitride film, such as a titanium carbonitride (TiCN)film, a zirconium carbonitride (ZrCN) film, a hafnium carbonitride(HfCN) film, a tantalum carbonitride (TaCN) film, an aluminumcarbonitride (AlCN) film, a molybdenum carbonitride (MoCN) film, etc. isformed.

In this case, the film-forming may be performed in a sequence similar tothat of any of the previous embodiments using a source gas including ametal element and a halogen element, instead of the chlorosilane-basedsource gas as in the previous embodiments. That is, a metallic thin filmmay be formed on the wafer 200 in the process chamber 201 by performinga cycle a predetermined number of times, the cycle including a processof supplying a source gas including a metal element and a halogenelement to the wafer 200 in the process chamber 201 and a process ofsupplying a reactive gas to the wafer 200.

Specifically, a metal-based thin film (a metal oxycarbonitride film, ametal oxycarbide film, or a metal carbonitride film) having apredetermined composition and a predetermined film thickness may beformed on the wafer 200 by performing a cycle a predetermined number oftimes, the cycle including: a process of forming a first layer includinga meal element, nitrogen, and carbon on the wafer 200 by alternatelyperforming a process of supplying a source gas including a metal elementand a halogen element to the wafer 200 in the process chamber 201 and aprocess of supplying a first reactive gas to the wafer 200 in theprocess chamber 201 a predetermined number of times; and a process offorming a second layer by supplying a second reactive gas, which isdifferent from the source gas and the first reactive gas, to the wafer200 in the process chamber 201 to modify the first layer.

In this case, for example, the flow rate of the first reactive gas ischanged in two steps as described above during the process of supplyingthe first reactive gas. In addition, during the process of supplying thesource gas or the process of supplying the second reactive gas, the flowrate of the source gas or the second reactive gas may be changed in twosteps as described above.

For example, when a metal-based thin film (a TiOCN film, a TiOC film, ora TiCN film) including Ti is formed, a gas including Ti and a chlorogroup such as titanium tetrachloride (TiCl₄) or a gas including Ti and afluoro group such as titanium tetrafluoride (TiF₄) or the like may beused as a source gas. Gases similar to those of the previous embodimentsmay be used as the first and second reactive gases. In this case,process conditions may be, for example, similar to those of theabove-mentioned embodiment.

In addition, for example, when a metal-based thin film (a ZrOCN film, aZrOC film, or a ZrCN film) including Zr is formed, a gas including Zrand a chloro group such as zirconium tetrachloride (ZrCl₄) or the like,or a gas including Zr and a fluoro group such as zirconium tetrafluoride(ZrF₄) or the like may be used as the source gas. Gases similar to thoseof the previous embodiments may be used as the first and second reactivegases. In this case, process conditions may be, for example, similar tothose of the above-mentioned embodiment.

Further, for example, when a metal-based thin film (a HfOCN film, a HfOCfilm, or a HfCN film) including Hf is formed, a gas including Hf and achloro group such as hafnium tetrachloride (HfCl₄) or the like, or a gasincluding Hf and a fluoro group such as hafnium tetrafluoride (HfF₄) orthe like may be used as the source gas. Gases similar to those of theprevious embodiments may be used as the first and second reactive gases.In this case, process conditions may be, for example, similar to thoseof the above-mentioned embodiment.

In addition, for example, when a metal-based thin film (a TaOCN film, aTaOC film, or a TaCN film) including Ta is formed, a gas including Taand a chloro group such as tantalum pentachloride (TaCl₅) or the like,or a gas including Ta and a fluoro group such as tantalum pentafluoride(TaF₅) or the like may be used as the source gas. Gases similar to thoseof the previous embodiments may be used as the first and second reactivegases. In this case, process conditions may be, for example, similar tothose of the above-mentioned embodiment.

In addition, for example, when a metal-based thin film (an AlOCN film,an AlOC film, or an AlCN film) including Al is formed, a gas includingAl and a chloro group such as aluminum trichloride (AlCl₃) or the like,or a gas including Al and a fluoro group such as aluminum trifluoride(AlF₃) or the like may be used as the source gas. Gases similar to thoseof the previous embodiments may be used as the first and second reactivegases. In this case, process conditions may be, for example, similar tothose of the above-mentioned embodiment.

In addition, for example, when a metal-based thin film (a MoOCN film, aMoOC film, or a MoCN film) including Mo is formed, a gas including Moand a chloro group such as molybdenum pentachloride (MoCl₅) or the like,or a gas including Mo and a fluoro group such as molybdenumpentafluoride (MoF₅) or the like may be used as the source gas. Gasessimilar to those of the previous embodiments may be used as the firstand second reactive gases. In this case, process conditions may be, forexample, similar to those of the above-mentioned embodiment.

That is, the present invention may also be preferably applied to a casein which a thin film having a specific element, such as a semiconductorelement or a metal element, is formed.

A plurality of process recipes (programs each storing a process sequenceor process conditions) that are used to form various thin films arepreferably prepared according to the details of substrate processing(film type, composition ratio, film quality, film thickness, etc. of thethin film to be formed). When substrate processing starts, anappropriate process recipe is preferably selected among the plurality ofprocess recipes, according to the details of substrate processing.Specifically, the plurality of process recipes that are individuallyprepared according to the details of substrate processing are preferablystored (installed) beforehand in the memory device 121 c included in thesubstrate processing apparatus via an electrical communication line or anon-transitory computer-readable recording medium on which the processrecipes are recorded (external memory device 123). In addition, whensubstrate processing starts, the CPU 121 a included in the substrateprocessing apparatus preferably appropriately selects a process recipematching the details of substrate processing among the plurality ofrecipes stored in the memory device 121 c. By configuring the pluralityof process recipes as described above, thin films having various filmtypes, composition ratios, film qualities, and film thicknesses may begenerally and reproducibly formed using one substrate processingapparatus. Furthermore, load on an operator's manipulation (for example,when a processing sequence or process conditions are input) may bereduced, and substrate processing may be rapidly started without causingerrors in manipulation.

However, the plurality of process recipes described above are notlimited to new ones, and may be prepared by, for example, modifyingprocess recipes installed in the substrate processing apparatus. When aprocess recipe is modified, the modified process recipe may be installedin the substrate processing apparatus via an electrical communicationline or a non-transitory computer-readable recording medium on which theprocess recipes are recorded. Otherwise, the existing process recipesinstalled in the substrate processing apparatus may be directly changedby manipulating the I/O device 122 included in the substrate processingapparatus.

In the previous embodiments, while the case in which the thin film isformed using the batch type substrate processing apparatus forprocessing a plurality of substrates at a time has been described, thepresent invention is not limited thereto and may be applied to the casein which the thin film is formed using a single wafer type substrateprocessing apparatus for processing one or a plurality of substrates ata time. In addition, in the previous embodiments, while the example inwhich the thin film is formed using the substrate processing apparatusincluding the hot wall type processing furnace has been described, thepresent invention is not limited thereto and may be applied to a case inwhich a thin film is formed using the substrate processing apparatusincluding a cold wall type processing furnace.

The previous embodiments may be appropriately combined and used.

Examples

As an example of the present invention, a SiOCN film was formed on awafer according to the film-forming sequence according to the firstembodiment described above. In addition, in a first TEA gas supplyprocess in step 2, the flow rate (first flow rate) of TEA gas was set tobe within a range of 200 to 1,000 sccm and a gas supply time was set tobe within a range of 10 to 20 seconds. In addition, in a second TEA gassupply process, the flow rate (second flow rate) of the TEA gas was setto be within a range of 100 to 500 sccm and a gas supply time was set tobe within a range of 20 to 100 seconds. The other film-formingconditions (process conditions in each step) were the same as those inthe first embodiment.

According to a comparative example, a SiOCN film was formed on a waferwithout changing the flow rate of TEA gas supplied into a processchamber in the film-forming sequence according to the first embodiment.In addition, in step 2 (TEA gas supply process), the flow rate of theTEA gas was set to be within a range of 200 to 1,000 sccm and a gassupply time was set to be within a range of 30 to 120 seconds. The otherfilm-forming conditions (process conditions in each step) were the sameas those in the first embodiment. As a result, in both the film-formingsequence according to the example of the present invention and thefilm-forming sequence according to the comparative example, a SiOCN filmhaving about 10 to 20% of carbon concentration was also formed. Inaddition, in the film-forming sequence according to the example of thepresent invention, a total supply rate (consumption rate) of the TEA gaswas less and a film-forming rate was higher, compared to thefilm-forming sequence according to the comparative example. In addition,in the film-forming sequence according to the example of the presentinvention, the total supply rate of the TEA gas was reduced to 60 to 70%of that in the film-forming sequence according to the comparativeexample.

According to the present invention, a method of manufacturing asemiconductor device, which is capable of reducing a total supply rateof reactive gases without lowering the concentrations of, for example,oxygen, nitrogen, and carbon contained in a thin film, a substrateprocessing apparatus, and a non-transitory computer-readable recordingmedium.

Exemplary Embodiments of the Present Invention

Exemplary embodiments of the present invention will now besupplementarily stated.

Supplementary Note 1

According to an embodiment of the present invention, there is provided amethod of manufacturing a semiconductor device, including: forming athin film on a substrate by performing a cycle a predetermined number oftimes, the cycle including: (a) supplying a source gas to the substratein a process chamber; and (b) supplying a reactive gas to the substratein the process chamber, wherein at least one of the steps (a) and (b)includes: (c) supplying the source gas or the reactive gas at a firstflow rate with an exhaust of an inside of the process chamber beingsuspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

Supplementary Note 2

In the method of Supplementary Note 1, the step (c) may include settinga degree of opening of an exhaust valve installed at an exhaust lineconfigured to exhaust the inside of the process chamber to a fullyclosed state, and the step (d) may include opening the exhaust valve.

Supplementary Note 3

In the method of Supplementary Note 1 or 2, the step (c) may includesuspending control of a degree of opening of an exhaust valve installedat an exhaust line configured to exhaust the inside of the processchamber, and the step (d) may include performing the control of thedegree of opening of the exhaust valve.

Supplementary Note 4

In the method of Supplementary Note 3, the step (c) may include settingthe degree of opening of the exhaust valve to a fully closed state.

Supplementary Note 5

In the method of Supplementary Note 1, the step (c) may include blockingan exhaust line configured to exhaust the inside of the process chamber,and the step (d) may include opening the exhaust line.

Supplementary Note 6

In the method of Supplementary Note 1 or 5, each of the steps (c) and(d) may include supplying an inert gas together with the source gas orthe reactive gas.

Supplementary Note 7

In the method of Supplementary Note 6, each of the steps (c) and (d) mayinclude maintaining a ratio of a flow rate of the source gas or thereactive gas to that of the inert gas at a constant level.

Supplementary Note 8

In the method of Supplementary Note 6, the step (c) may includesupplying the inert gas at a third flow rate, and the step (d mayinclude supplying the inert gas at a fourth flow rate that is less thanthe third flow rate.

Supplementary Note 9

In the method of Supplementary Note 8, during the steps (c) and (d), aratio of the first flow rate to the third flow rate is same as a ratioof the second flow rate to the fourth flow rate.

Supplementary Note 10

In the method of Supplementary Note 8, during the steps (c) and (d), aratio of the first flow rate to a sum of the first flow rate and thethird flow rate is same as a ratio of the second flow rate to a sum ofthe second flow rate and the fourth flow rate.

Supplementary Note 11

In the method of any one of Supplementary Notes 1 to 10, each of thesteps (c) and (d) may include maintaining a partial pressure of thesource gas or the reactive gas in respective step at a constant level atleast after the inner pressure of the process chamber reaches thepredetermined pressure.

Supplementary Note 12

In the method of any one of Supplementary Notes 1 to 11, the step (a)may include the steps (c) and (d).

Supplementary Note 13

In the method of any one of Supplementary Notes 1 to 12, the step (b)may include the steps (c) and (d).

Supplementary Note 14

In the method of any one of Supplementary Notes 1 to 13, the reactivegas may include a carbon-containing gas.

Supplementary Note 15

In the method of any one of Supplementary Notes 1 to 14, the reactivegas may include a gas containing carbon and nitrogen.

Supplementary Note 16

In the method of any one of Supplementary Notes 1 to 15, the reactivegas may include at least one of a hydrocarbon-based gas and anamine-based gas.

Supplementary Note 17

According to another embodiment of the present invention, there isprovided a substrate processing method, including forming a thin film ona substrate by performing a cycle a predetermined number of times, thecycle including: (a) supplying a source gas to the substrate in aprocess chamber; and (b) supplying a reactive gas to the substrate inthe process chamber, wherein at least one of the steps (a) and (b)includes: (c) supplying the source gas or the reactive gas at a firstflow rate with an exhaust of an inside of the process chamber beingsuspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

Supplementary Note 18

According to still another embodiment of the present invention, there isprovided a substrate processing apparatus including: a process chamberconfigured to accommodate a substrate; a source gas supply systemconfigured to supply a source gas into the process chamber; a reactivegas supply system configured to supply a reactive gas into the processchamber; an exhaust system configured to exhaust an inside of theprocess chamber; a pressure regulator configured to regulate pressure inthe process chamber; and a control unit configured to control the sourcegas supply system, the reactive gas supply system, the exhaust system,and the pressure regulator to form a thin film on the substrate byperforming a cycle a predetermined number of times, the cycle including:(a) supplying a source gas to the substrate in a process chamber; and(b) supplying a reactive gas to the substrate in the process chamber,wherein at least one of the steps (a) and (b) includes: (c) supplyingthe source gas or the reactive gas at a first flow rate with an exhaustof an inside of the process chamber being suspended until an innerpressure of the process chamber reaches a predetermined pressure; and(d) supplying the source gas or the reactive gas at a second flow rateless than the first flow rate with the exhaust of the inside of theprocess chamber being performed while maintaining the inner pressure ofthe process chamber at the predetermined pressure after the innerpressure of the process chamber reaches the predetermined pressure.

Supplementary Note 19

According to yet another embodiment of the present invention, there isprovided a program that causes a computer to perform a sequence offorming a thin film on a substrate by performing a cycle a predeterminednumber of times, the cycle including: (a) supplying a source gas to thesubstrate in a process chamber; and (b) supplying a reactive gas to thesubstrate in the process chamber, wherein at least one of the sequences(a) and (b) includes: (c) supplying the source gas or the reactive gasat a first flow rate with an exhaust of an inside of the process chamberbeing suspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

Supplementary Note 20

According to yet another embodiment of the present invention, there isprovided a non-transitory computer-readable recording medium storing aprogram that causes a computer to perform a sequence of forming a thinfilm on a substrate by performing a cycle a predetermined number oftimes, the cycle including: (a) supplying a source gas to the substratein a process chamber; and (b) supplying a reactive gas to the substratein the process chamber, wherein at least one of the sequences (a) and(b) includes: (c) supplying the source gas or the reactive gas at afirst flow rate with an exhaust of an inside of the process chamberbeing suspended until an inner pressure of the process chamber reaches apredetermined pressure; and (d) supplying the source gas or the reactivegas at a second flow rate less than the first flow rate with the exhaustof the inside of the process chamber being performed while maintainingthe inner pressure of the process chamber at the predetermined pressureafter the inner pressure of the process chamber reaches thepredetermined pressure.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising: forming a thin film on a substrate by performing a cycle apredetermined number of times, the cycle comprising: (a) supplying asource gas to the substrate in a process chamber; and (b) supplying areactive gas to the substrate in the process chamber, wherein at leastone of (a) and (b) includes: (c) supplying a gas used in the at leastone of (a) and (b) at a first flow rate with an exhaust of an atmospherein the process chamber through an exhaust line being suspended by fullyclosing an exhaust valve installed at the exhaust line to increase aninner pressure in the process chamber until the inner pressure of theprocess chamber reaches a predetermined pressure; and (d) supplying thegas used in the at least one of (a) and (b) at a second flow rate lessthan the first flow rate with the exhaust of the atmosphere in theprocess chamber through the exhaust line being performed by opening theexhaust valve while maintaining the inner pressure of the processchamber at the predetermined pressure by controlling degree of openingof the exhaust valve after the inner pressure of the process chamberreaches the predetermined pressure.
 2. The method of claim 1, wherein(c) comprises suspending control of the degree of opening of the exhaustvalve, and (d) comprises performing the control of the degree of openingof the exhaust valve.
 3. The method of claim 2, wherein (c) comprisessetting the degree of opening of the exhaust valve to a fully closedstate.
 4. The method of claim 1, wherein (c) comprises blocking theexhaust line, and (d) comprises opening the exhaust line.
 5. The methodof claim 1, wherein each of (c) and (d) comprises supplying an inert gastogether with the gas used in the at least one of (a) and (b).
 6. Themethod of claim 5, wherein each of (c) and (d) comprises maintaining aratio of a flow rate of the gas used in the at least one of (a) and (b)to that of the inert gas at a constant level.
 7. The method of claim 5,wherein (c) comprises supplying the inert gas at a third flow rate, and(d) comprises supplying the inert gas at a fourth flow rate that is lessthan the third flow rate.
 8. The method of claim 7, wherein during (c)and (d), a ratio of the first flow rate to the third flow rate is sameas a ratio of the second flow rate to the fourth flow rate.
 9. Themethod of claim 7, wherein during (c) and (d), a ratio of the first flowrate to a sum of the first flow rate and the third flow rate is same asa ratio of the second flow rate to a sum of the second flow rate and thefourth flow rate.
 10. The method of claim 1, wherein each of (c) and (d)comprises maintaining a partial pressure of the gas used in the at leastone of (a) and (b) at a constant level at least after the inner pressureof the process chamber reaches the predetermined pressure.
 11. Themethod of claim 1, wherein (a) comprises (c) and (d).
 12. The method ofclaim 1, wherein (b) comprises (c) and (d).
 13. The method of claim 1,wherein the reactive gas comprises at least one selected from a groupconsisting of a gas containing carbon and nitrogen and acarbon-containing gas.
 14. The method of claim 1, wherein the reactivegas comprises at least one selected from a group consisting of ahydrocarbon-based gas and an amine-based gas.
 15. A method ofmanufacturing a semiconductor device, comprising: forming a thin film ona substrate by performing a cycle a predetermined number of times, thecycle comprising: (a) supplying a source gas to the substrate in aprocess chamber; and (b) supplying a reactive gas to the substrate inthe process chamber, wherein (a) includes: (c) supplying the source gasat a first flow rate with an exhaust of an atmosphere in the processchamber through an exhaust line being suspended by fully closing anexhaust valve installed at the exhaust line to increase an innerpressure in the process chamber until the inner pressure of the processchamber reaches a predetermined pressure; and (d) supplying the sourcegas at a second flow rate less than the first flow rate with the exhaustof the atmosphere in the process chamber being performed by opening theexhaust valve while maintaining the inner pressure of the processchamber at the predetermined pressure by controlling degree of openingof the exhaust valve after the inner pressure of the process chamberreaches the predetermined pressure.
 16. The method of claim 15, wherein(b) includes: (e) supplying the reactive gas at third flow rate with theexhaust of the atmosphere in the process chamber through athe exhaustline being suspended by fully closing an exhaust valve until the innerpressure of the process chamber reaches a predetermined pressure; and(f) supplying the reactive gas at fourth flow rate less than the thirdflow rate with the exhaust of the atmosphere in the process chamberbeing performed by opening the exhaust valve while maintaining the innerpressure of the process chamber at the predetermined pressure bycontrolling degree of opening of the exhaust valve after the innerpressure of the process chamber reaches the predetermined pressure. 17.A method of manufacturing a semiconductor device, comprising: forming athin film on a substrate by performing a cycle a predetermined number oftimes, the cycle comprising: (a) supplying a source gas to the substratein a process chamber; and (b) supplying a reactive gas to the substratein the process chamber, wherein (b) includes: (c) supplying the reactivegas at a first flow rate with an exhaust of an atmosphere in the processchamber through an exhaust line being suspended by fully closing anexhaust valve installed at the exhaust line to increase an innerpressure in the process chamber until the inner pressure of the processchamber reaches a predetermined pressure; and (d) supplying the reactivegas at a second flow rate less than the first flow rate with the exhaustof the atmosphere in the process chamber being performed by opening theexhaust valve while maintaining the inner pressure of the processchamber at the predetermined pressure by controlling degree of openingof the exhaust valve after the inner pressure of the process chamberreaches the predetermined pressure.